CN106460097B - The manufacture method of copper alloy plate and copper alloy plate - Google Patents

Abstract

The present invention provides a copper alloy sheet excellent in stress corrosion cracking resistance, stress relaxation characteristics, tensile strength, yield strength, electrical conductivity, bending workability, and solder wettability. The copper alloy plate contains 4 to 14% by mass of Zn, 0.1 to 1% by mass of Sn, 0.005 to 0.08% by mass of P, and 1.0 to 2.4% by mass of Ni, and the remainder is composed of Cu and unavoidable impurities, and has The following relationship, that is, 7≤[Zn]+3×[Sn]+2×[Ni]≤18, 0≤[Zn]-0.3×[Sn]-1.8×[Ni]≤11, 0.3≤(3×[ Ni]+0.5×[Sn])/[Zn]≤1.6, 1.8≤[Ni]/[Sn]≤10, 16≤[Ni]/[P]≤250, the average grain size is 2～9μm, round The average particle diameter of the precipitates in shape or oval shape is 3 to 75 nm or the ratio of the number of precipitates with a particle diameter of 3 to 75 nm in the precipitates is 70% or more, and the electrical conductivity is 24% IACS or more, The stress relaxation rate under the conditions of 150° C. and 1000 hours as the stress relaxation resistance is 25% or less.

Description

Copper alloy plate and manufacturing method of copper alloy plate

technical field

The present invention relates to a copper alloy plate with excellent stress corrosion cracking resistance, stress relaxation characteristics, tensile strength, yield strength, electrical conductivity, bending processability, and solder wettability, especially a copper alloy plate for terminals/connectors, Copper alloy plate for electric/electronic components and method for producing the copper alloy plate.

This application claims priority based on Japanese Patent Application No. 2014-196430 for which it applied in Japan on September 26, 2014, and uses the content here.

Background technique

Conventionally, as constituent materials for connectors, terminals, relays, springs, switches, semiconductors, lead frames, etc. used in automotive components, electrical components, electronic components, communication devices, electronic/electrical devices, etc., highly conductive and high-strength copper alloy plate. However, along with recent reductions in size, weight reduction, and performance enhancement of related devices, improvement in characteristics of constituent materials used for these devices has been strictly required. For example, an ultra-thin plate is used in the spring contact portion of a connector, but in order to achieve thinning, the high-strength copper alloy constituting the ultra-thin plate is required to have high strength and a high balance between elongation and strength. It is further required to be excellent in productivity and economical efficiency, and to have no problems in electrical conductivity, corrosion resistance (stress corrosion cracking resistance, dezincification corrosion resistance, migration resistance), stress relaxation characteristics, and solder wettability to suppress the deterioration of materials in use. .

However, strength and conductivity are inverse characteristics, and as strength increases, conductivity generally decreases. In addition, for example, in places where the operating environment temperature is high, such as near the engine room of a car, it can rise to 100°C to 150°C, for example, and there are components that require more excellent stress relaxation and heat resistance. In addition, with the advancement of automotive engine electronic control technology in recent years, the number of components used at high temperatures has increased, and copper alloy materials that can ensure high reliability in high-temperature environments are required. Of course, automotive components or motor/electronic device components are in a state of fierce competition, so low-cost copper alloy raw materials are required. Furthermore, from the viewpoint of global procurement, copper alloy raw materials that are easy to manufacture are urgently required.

Here, beryllium copper, phosphor bronze, nickel silver, brass, or Sn-added brass are generally known as high-conductivity high-strength copper alloys.

Furthermore, Cu—Zn—Sn alloys such as those disclosed in Patent Document 1 are known as alloys for satisfying the requirements of high electrical conductivity and high strength.

Patent Document 1: Japanese Patent Laid-Open No. 2007-056365

However, general high-strength copper alloys such as the above-mentioned beryllium copper, phosphor bronze, nickel silver, and brass have the following problems and cannot meet the above-mentioned requirements.

Beryllium copper has the highest strength among copper alloys, but beryllium is very harmful to the human body (especially, even a very small amount of beryllium vapor is very dangerous in a molten state). Therefore, it is difficult to dispose of beryllium-copper parts or products containing them (in particular, incineration), and the initial cost required for the melting equipment used for manufacturing becomes extremely high. Therefore, in order to obtain predetermined characteristics, it is necessary to perform solution treatment at the final stage of production, and there is a problem in economical efficiency including production cost.

Phosphor bronze and nickel silver have poor hot workability and are difficult to produce by hot rolling, so they are usually produced by horizontal continuous casting. Consequently, productivity is poor, energy costs are high, and yield is poor.

In addition, phosphor bronze for springs or nickel silver for springs, which are representative types of high-strength copper alloys, contain a large amount of expensive Sn and Ni, so they are poor in electrical conductivity and have problems in economical efficiency.

The price of Zn, which is the main element of brass, is lower than that of Cu. By adding Zn to Cu, the density is reduced, and the strength, namely tensile strength, yield strength or yield stress, spring limit value, and fatigue strength are increased. On the other hand, in the case of brass, as the Zn content increases, the stress corrosion cracking sensitivity becomes very high, and the reliability as a material is impaired. On the other hand, brass is known to have poor stress relaxation characteristics and cannot be used at all in components that reach high temperatures such as around the engine compartment. Furthermore, as the Zn content increases, the strength improves, but the ductility and bending workability deteriorate, and the balance between strength and ductility deteriorates.

As mentioned above, although brass and brass with only Sn added are cheap, they cannot meet the strength requirements, and their stress relaxation characteristics and electrical conductivity are poor, and there are problems in corrosion resistance (stress corrosion and dezincification corrosion). The material constituting the product that realizes miniaturization and high performance is not suitable.

Therefore, this general high-conductivity/high-strength copper alloy cannot satisfy the components constituting materials of various devices that tend to be miniaturized, light-weight, and high-performance as described above, and there is a strong demand for the development of a new type of copper alloy. Highly conductive, high strength copper alloy.

Furthermore, the Cu—Zn—Sn alloy described in Patent Document 1 is not sufficient in many characteristics including electrical conductivity and strength.

The present invention was made to solve the above-mentioned conventional technical problems, and its object is to provide a copper alloy excellent in stress corrosion cracking resistance, stress relaxation characteristics, tensile strength, yield strength, electrical conductivity, bending workability, and solder wettability. The alloy plate, in particular, provides a copper alloy plate that can withstand harsh use environments and is suitable for terminals/connectors and electrical/electronic components with high reliability, and a method for manufacturing the copper alloy plate.

Contents of the invention

In order to solve the above-mentioned problems, the inventors of the present invention have repeatedly studied from various angles and repeated various researches and experiments, and found that the following method can achieve excellent cost performance, low density, high strength and elongation/bending workability, and electrical conductivity. Balance, and stress corrosion cracking resistance, stress relaxation characteristics of copper alloys, and can cope with various use environments, so that the present invention is completed, that is, first in the Cu-Zn alloy containing 4 to 14 mass % of Zn Ni and Sn are added in appropriate amounts, and in order to optimize the interaction between Ni and Sn, the total content and content ratio of Ni and Sn are set in an appropriate range. In addition, in view of the interaction between Zn and Ni and Sn, With 3 composition relations f1=[Zn]+3×[Sn]+2×[Ni], f2=[Zn]-0.3×[Sn]-1.8×[Ni], and f3=(3×[Ni] ]+0.5×[Sn])/[Zn] to adjust Zn, Ni, and Sn so that they become appropriate values at the same time, and set the content ratio of Ni amount to Sn amount, and P amount to Ni amount within an appropriate range, and appropriately The size and crystal grain size of the formed precipitates are adjusted.

Specifically, by dissolving an appropriate amount of Zn, Ni, and Sn in the matrix and containing P, high strength can be obtained without impairing ductility and bending workability. In addition, the atomic valence (or the number of valence electrons, the same below) is 4 valence (4 valence electrons) Sn, 2 valence Zn, Ni and 5 valence P, thereby making the stress corrosion cracking resistance and stress The relaxation characteristics are improved, and at the same time, the stacking fault energy is reduced to make crystal grains finer during recrystallization. Furthermore, by forming a fine compound mainly composed of Ni and P, crystal grain growth is suppressed, and fine crystal grains are maintained.

Furthermore, by making the crystal grains (recrystallized grains) finer, the strength mainly including the tensile strength and yield strength can be significantly improved. That is, the strength increases as the average crystal grain size gradually decreases. Specifically, adding Zn, Sn, and Ni to Cu has the effect of increasing the nucleation sites of recrystallization nuclei. Adding P and Ni to the Cu-Zn-Sn-Ni alloy has the effect of suppressing the growth of crystal grains. Therefore, by utilizing these effects, a Cu—Zn—Sn—Ni—P based alloy having fine crystal grains can be obtained. It is considered that one of the main reasons for the increase in the nucleation sites of recrystallization nuclei is that the stacking fault energy is reduced by adding Zn, Ni, and Sn having atomic valences of divalent, divalent, and tetravalent, respectively. It is considered that the reason for suppressing the growth of the generated fine recrystallized grains in a fine state is that fine precipitates are generated by the addition of P and Ni. However, focusing only on ultra-miniaturization of recrystallized grains, the balance of strength, elongation, and bendability cannot be achieved. It was found that, in order to secure a balance, there is room for miniaturization of recrystallized grains, and it is found that a region with a size of a certain range of miniaturized crystal grains is good. With regard to the miniaturization or superfineness of crystal grains, the minimum crystal grain size in the standard photograph described in JIS H 0501 is 0.010 mm. Based on this, it is believed that those with an average crystal grain size smaller than 0.010 mm can be said to have been finely grained.

By dissolving Zn, Ni, and Sn in Cu, the strength is improved without impairing the ductility and bending workability, and in order to improve the stress relaxation characteristics and stress corrosion cracking resistance, various viewpoints are required. The interaction between elements represented by the properties of Zn, Ni, and Sn elements is considered. That is, only specifying the content of each element of Zn, Ni, and Sn does not necessarily make the stress relaxation characteristics and stress corrosion cracking resistance good, and obtain high strength without impairing ductility and bending workability.

Therefore, it is necessary to set the three composition relations within the specified range, namely composition relation f1=[Zn]+3×[Sn]+2×[Ni], composition relation f2=[Zn]-0.3× [Sn]−1.8×[Ni], and f3=(3×[Ni]+0.5×[Sn])/[Zn].

Even when the interaction of Zn, Ni, and Sn elements is considered, the lower limit values of the composition relations f1 and f2 are the minimum necessary values for obtaining high strength. On the other hand, if the composition relation f1 If f2 exceeds the upper limit or falls below the lower limit of composition relation f3, the strength will increase, but the stress relaxation characteristics and stress corrosion cracking resistance will be impaired.

In addition, the upper limit value of the composition relational expression f1=[Zn]+3×[Sn]+2×[Ni] is a value whether or not the electrical conductivity of the alloy of the present invention exceeds 24% IACS.

The upper limit of the composition relationship f2=[Zn]-0.3×[Sn]-1.8×[Ni] is also used to obtain excellent stress relaxation characteristics, stress corrosion cracking resistance, good ductility, bending workability and Boundary value for solder wettability. As described above, the critical disadvantages of Cu—Zn alloys are high susceptibility to stress corrosion cracking and poor stress relaxation characteristics.

The lower limit of the composition relation f3=(3×[Ni]+0.5×[Sn])/[Zn] is a boundary value for obtaining good stress relaxation properties. As described above, the Cu—Zn alloy is an alloy excellent in cost performance, but lacks stress relaxation characteristics, and even if it has high strength, it cannot effectively utilize the high strength. In general, brass alloys lack stress relaxation characteristics, but by optimizing the balance (3×[Ni]+0.5×[Sn]) and [Zn], that is, the compounding ratio, higher stress relaxation characteristics can be realized . When it is an upper limit, the amount of Ni and Sn increases, and the cost increases, or the electrical conductivity is deteriorated, and the stress relaxation characteristic is also saturated.

In addition, in the present application, it is important to set the Ni amount to the Sn amount, and the P amount to the Ni amount to be appropriate content ratios, whereby excellent stress relaxation characteristics, strength, and bendability can be realized. In particular, in order to improve the stress relaxation of Cu-Zn alloys, the first requirement is to add 1 to 2.4% by mass of Ni and 0.1 to 1% by mass of Sn together as the first condition, followed by the content ratio of Ni and Sn, and it is necessary to formulate the composition relation f4 = [Ni]/[Sn] is set within the specified range. Details will be described later, but at least 3.5 or more Ni atoms are required for one Sn atom. In addition, regarding Ni and P, which are important for stress relaxation characteristics, crystal grain size, strength, and bending workability, it is necessary to understand the composition relationship from the relationship between Ni and P in solid solution and the compound of Ni and P precipitated. The formula f5=[Ni]/[P] is set within a predetermined range.

In addition, in the above-mentioned copper alloy sheet, it is preferable to perform a recovery heat treatment step after the finish cold rolling step, and perform heat treatment corresponding thereto. At this time, since the recovery heat treatment is performed, the stress relaxation rate, Young's modulus, spring limit value, and elongation rate are increased.

The method of manufacturing the above-mentioned copper alloy sheet includes, in order, an ingot manufacturing process and a hot rolling process in which the composition is formulated, a continuous casting process in which the hot rolling process is omitted in some cases, a cold rolling process, a recrystallization heat treatment process, and a finishing cold rolling process. , the hot rolling start temperature of the hot rolling process is 800-950°C, the final rolling is finished at 750°C-500°C, and thereafter, forced cooling is performed by air cooling or water cooling until cooling to normal temperature. The recrystallization heat treatment process includes a batch type of heating for a long time and a continuous heat treatment method of continuously heating at a high temperature for a short time. Tensile bending straightening for improving the strain of the material may be performed after final finish rolling. In addition, recovery heat treatment is sometimes carried out by means of continuous heat treatment, or, in addition, when used in terminals/connectors and electrical/electronic components, electroplating such as hot-dip Sn plating and reflow Sn plating is included regardless of the recovery heat treatment process. Processing procedure.

In addition, depending on the thickness of the copper alloy sheet, the paired cold rolling step and the annealing step may be performed one or more times between the hot rolling step and the cold rolling step.

In addition, the manufacturing method of the copper alloy plate used especially for terminals/connectors, etc. is manufactured by the following method. Preferably, the cold working rate in the cold rolling process is 55% or more, and the recrystallization heat treatment process includes: a heating step, using continuous a heat treatment furnace heating the copper alloy material to a prescribed temperature; a maintaining step of maintaining the copper alloy material at a prescribed temperature for a prescribed time after the heating step; and a cooling step of cooling the copper alloy material after the maintaining step To a predetermined temperature, in the recrystallization heat treatment process, the maximum attainable temperature of the copper alloy material is set as Tmax (°C), and the temperature range from the temperature 50°C lower than the maximum attainable temperature of the copper alloy material to the maximum attainable temperature When the holding time of medium heating is set as tm (min), 560≤Tmax≤790, 0.04≤tm≤1.0, 520≤It1=(Tmax-30×tm ^-1/2 )≤690, in addition, recovery heat treatment process is also included , or Sn plating, the recovery heat treatment process includes: a heating step, after the finishing cold rolling process, the copper alloy material is heated to a specified temperature; a holding step, after the heating step, the copper alloy material is maintained at a specified temperature for a specified time; And a cooling step, after the holding step, cooling the copper alloy material to a prescribed temperature, wherein the maximum attainable temperature of the copper alloy material is set as Tmax2 (°C), which is 50°C lower than the maximum attainable temperature of the copper alloy material The heating and holding time from the temperature of ℃ to the temperature range of the highest reaching temperature is set as tm2 (min), 150≤Tmax2≤580, 0.02≤tm2≤100, 120≤It2=(Tmax2-25×tm2 ^-1/2 )≤ 390. The stress relaxation rate, Young's modulus, spring limit value, bending workability, and elongation can be improved by performing recrystallization heat treatment and recovery heat treatment steps at high temperature for a short period of time.

The present invention has been completed based on the above findings. The copper alloy sheet according to the first aspect of the present invention contains 4 to 14 mass % of Zn, 0.1 to 1 mass % of Sn, 0.005 to 0.08 mass % of P and 1.0 to 2.4 mass % Mass % of Ni, and the remainder is composed of Cu and unavoidable impurities, Zn content [Zn] mass %, Sn content [Sn] mass %, P content [P] mass % and Ni content [Ni] mass % has the following relationship:

7≤[Zn]+3×[Sn]+2×[Ni]≤18,

0≤[Zn]-0.3×[Sn]-1.8×[Ni]≤11,

0.3≤(3×[Ni]+0.5×[Sn])/[Zn]≤1.6,

1.8≤[Ni]/[Sn]≤10,

16≤[Ni]/[P]≤250,

The average crystal particle size is 2-9 μm, the average particle size of the circular or elliptical precipitates is 3-75 nm, or the ratio of the number of precipitates with a particle size of 3-75 nm in the precipitates is 70 % or more, the electrical conductivity is 24% IACS or more, and as the stress relaxation resistance characteristic, the stress relaxation rate is 25% or less under the conditions of 150°C and 1000 hours.

The copper alloy sheet of the second aspect of the present invention contains 4 to 12 mass % of Zn, 0.1 to 0.9 mass % of Sn, 0.008 to 0.07 mass % of P and 1.05 to 2.2 mass % of Ni, and the remainder is composed of Cu And unavoidable impurity composition, the content [Zn] mass % of Zn, the content [Sn] mass % of Sn, the content [P] mass % of P and the following relationship between the content [Ni] mass % of Ni:

7≤[Zn]+3×[Sn]+2×[Ni]≤16,

0≤[Zn]-0.3×[Sn]-1.8×[Ni]≤9,

0.3≤(3×[Ni]+0.5×[Sn])/[Zn]≤1.3,

2≤[Ni]/[Sn]≤8,

18≤[Ni]/[P]≤180,

The average crystal particle size is 2-9 μm, the average particle size of the circular or elliptical precipitates is 3-60 nm, or the ratio of the number of precipitates with a particle size of 3-60 nm in the precipitates is 70 % or more, the electrical conductivity is 26% IACS or more, and as the stress relaxation resistance characteristic, the stress relaxation rate is 23% or less under the conditions of 150°C and 1000 hours.

The copper alloy sheet according to the third aspect of the present invention, wherein the copper alloy sheet further contains 0.0005% by mass to 0.05% by mass, and a total of 0.0005% by mass to 0.2% by mass, selected from the group consisting of Al and Fe. , Co, Mg, Mn, Ti, Zr, Cr, Si, Sb, As, Pb, and at least one or two or more rare earth elements.

The copper alloy sheet according to the fourth aspect of the present invention, wherein the above-mentioned copper alloy sheet is manufactured through the following manufacturing process, the manufacturing process includes: a finish cold rolling process of cold rolling copper alloy material; In the recovery heat treatment process performed after the cold rolling process, when the electrical conductivity is C (%IACS), and the effective stress at 150°C and 1000 hours is Pw (N/mm ² ), the following relationship is established:

Pw≥300,

Pw×(C/100) ^1/2 ≥190,

The ratio YS 90 /YS 0 of the yield strength YS ₉₀ in the direction of 90 degrees relative to the rolling direction to the yield strength YS ₀ in the direction of 0 degrees relative to the rolling direction, YS ₉₀ /YS ₀ , is in the range of 0.95≤YS ₉₀ /YS ₀ ≤1.07.

The copper alloy sheet according to a fifth aspect of the present invention is used for electronic/electric device components such as connectors, terminals, relays, switches, and semiconductor applications.

A method for producing a copper alloy sheet according to a sixth aspect of the present invention is a method for producing a copper alloy sheet as described above, wherein the method sequentially includes a hot rolling step, a cold rolling step, a recrystallization heat treatment step, and a finish cold rolling step , the cold working rate in the cold rolling process is more than 55%, and the recrystallization heat treatment process includes: a heating step, using a continuous heat treatment furnace, to heat the cold-rolled copper alloy material to a specified temperature; After the step, maintaining the copper alloy material at a specified temperature for a specified time; and a cooling step, after the maintaining step, cooling the copper alloy material to a specified temperature, and in the recrystallization heat treatment process, the copper alloy material When the maximum attained temperature is Tmax (°C), and the time for heating and holding in the temperature range from a temperature 50°C lower than the maximum attained temperature of the copper alloy material to the maximum attained temperature is defined as tm (min),

560≤Tmax≤790,

0.04≤tm≤1.0,

520≤It1=(Tmax-30×tm ^-1/2 )≤690, and in the recrystallization heat treatment step, in the temperature range from 50°C lower than the maximum attained temperature to 400°C, at 5°C/ Seconds or more conditions for cooling. In addition, depending on the thickness of the copper alloy sheet, one or more paired cold rolling and annealing steps may be performed between the hot rolling step and the cold rolling step.

A copper alloy sheet manufacturing method according to a seventh aspect of the present invention includes a recovery heat treatment step performed after the finish cold rolling step, and the recovery heat treatment step includes a heating step of heating the copper alloy material after finish cold rolling to a prescribed temperature; a holding step, after the heating step, keeping the copper alloy material at a prescribed temperature for a prescribed time; and a cooling step, cooling the copper alloy material to a prescribed temperature after the keeping step, and keeping the copper alloy material When the maximum attained temperature is set to Tmax2 (°C), and the time for heating and holding in the temperature range from a temperature 50°C lower than the maximum attained temperature of the copper alloy material to the maximum attained temperature is set to tm2 (min) as follows:

150≤Tmax2≤580,

0.02≤tm2≤100,

120≤It2=(Tmax2−25×tm2 ^−1/2 )≤390.

The method for manufacturing a copper alloy sheet according to an eighth aspect of the present invention is a method for manufacturing a copper alloy sheet as described above, wherein the method includes a paired cold rolling process and an annealing process, a cold rolling process, and a recrystallization heat treatment process , a finishing cold rolling process and a recovery heat treatment process, and is configured so that no hot working is required, and after one or more paired cold rolling processes and annealing processes are performed, the combination of the cold rolling process and the recrystallization treatment is performed process, and a combination of one or both of the finish cold rolling process and the recovery heat treatment process. The cold working rate in the cold rolling process is 55% or more, and the recrystallization heat treatment process includes: a heating step, using a continuous heat treatment furnace, to heat the cold-rolled copper alloy material to a predetermined temperature; a holding step, in the heating step Afterwards, maintaining the copper alloy material at a specified temperature for a specified time; and a cooling step, after the maintaining step, cooling the copper alloy material to a specified temperature, and in the recrystallization heat treatment process, the highest temperature of the copper alloy material is When the attainment temperature is Tmax (°C), and the time for heating and holding in the temperature range from a temperature 50°C lower than the maximum attainment temperature of the copper alloy material to the maximum attainment temperature is tm (min),

560≤Tmax≤790,

0.04≤tm≤1.0,

520≤It1=(Tmax-30×tm ^-1/2 )≤690, and in the recrystallization heat treatment step, in the temperature range from 50°C lower than the maximum attained temperature to 400°C, at 5°C/ Seconds or more conditions for cooling. The recovery heat treatment process includes: a heating step of heating the copper alloy material after finish cold rolling to a predetermined temperature; a holding step of maintaining the copper alloy material at a predetermined temperature for a predetermined time after the heating step; and a cooling step of After the holding step, the copper alloy material is cooled to a specified temperature, the maximum attained temperature of the copper alloy material is set as Tmax2 (° C.), and the temperature lower than the maximum attained temperature of the copper alloy material by 50° C. to the maximum attained temperature is When the heating retention time in the temperature zone is set to tm2(min), it is as follows:

150≤Tmax2≤580,

0.02≤tm2≤100,

120≤It2=(Tmax2−25×tm2 ^−1/2 )≤390.

According to the present invention, it is possible to provide a copper alloy sheet excellent in stress corrosion cracking resistance, stress relaxation characteristics, tensile strength, yield strength, electrical conductivity, bending workability, and solder wettability, and in particular to provide a copper alloy sheet capable of withstanding A copper alloy plate suitable for high reliability terminals/connectors and electric/electronic components in a harsh service environment, and a method for manufacturing the copper alloy plate.

Detailed ways

Hereinafter, the copper alloy sheet and the manufacturing method of the copper alloy sheet which concern on embodiment of this invention are demonstrated. The copper alloy sheet of this embodiment is used as a constituent material of connectors, terminals, relays, springs, switches, semiconductors, lead frames, etc. used in automotive components, electrical components, electronic components, communication devices, electronic/electrical devices, and the like.

However, in this specification, an element symbol in parentheses such as [Zn] represents the content (mass %) of the element.

In addition, in the present embodiment, a plurality of composition relational expressions are defined as follows using the expression method of the content. In addition, effectively added elements such as Co and Fe and unavoidable impurities have little influence on the properties of the copper alloy sheet at the content specified in this embodiment, so they are not included in each calculation formula described later. In addition, less than 0.005% by mass of Cr, for example, is regarded as an unavoidable impurity.

Composition relation f1=[Zn]+3×[Sn]+2×[Ni]

Composition relation f2=[Zn]-0.3×[Sn]-1.8×[Ni]

Composition relation f3=(3×[Ni]+0.5×[Sn])/[Zn]

Composition relation f4=[Ni]/[Sn]

Composition relation f5=[Ni]/[P]

The copper alloy sheet according to the first embodiment of the present invention contains 4 to 14% by mass of Zn, 0.1 to 1% by mass of Sn, 0.005 to 0.08% by mass of P, and 1.0 to 2.4% by mass of Ni, and the remainder consists of Composition of Cu and unavoidable impurities, the composition relationship f1 is in the range of 7≤f1≤18, the composition relationship f2 is in the range of 0≤f2≤11, the composition relationship f3 is in the range of 0.3≤f3≤1.6, and the composition relationship f4 In the range of 1.8≤f4≤10, the composition relation f5 is in the range of 16≤f5≤250.

The copper alloy sheet according to the second embodiment of the present invention contains 4 to 12 mass % of Zn, 0.1 to 0.9 mass % of Sn, 0.008 to 0.07 mass % of P, and 1.05 to 2.2 mass % of Ni, and the remainder is composed of Composition of Cu and unavoidable impurities, the composition relationship f1 is in the range of 7≤f1≤16, the composition relationship f2 is in the range of 0≤f2≤9, the composition relationship f3 is in the range of 0.3≤f3≤1.3, and the composition relationship f4 In the range of 2≤f4≤8, the composition relation f5 is in the range of 18≤f5≤180.

The copper alloy sheet according to the third embodiment of the present invention contains 4 to 14 mass % of Zn, 0.1 to 1 mass % of Sn, 0.005 to 0.08 mass % of P, 1.0 to 2.4 mass % of Ni, and 0.0005 mass % % to 0.05 mass % and a total of 0.0005 mass % to 0.2 mass % of at least One or more than two kinds, the rest of which is composed of Cu and unavoidable impurities, the composition relation f1 is in the range of 7≤f1≤18, the composition relation f2 is in the range of 0≤f2≤11, and the composition relation f3 is in the range of 0.3 ≤f3≤1.6, the composition relation f4 is in the range of 1.8≤f4≤10, and the composition relation f5 is in the range of 16≤f5≤250.

The copper alloy sheet according to the fourth embodiment of the present invention contains 4 to 12 mass % of Zn, 0.1 to 0.9 mass % of Sn, 0.008 to 0.07 mass % of P, 1.05 to 2.2 mass % of Ni, and 0.0005 mass % of Ni respectively. % to 0.05 mass % and a total of 0.0005 mass % to 0.2 mass % of at least 1 or more than 2 kinds, and the rest is composed of Cu and unavoidable impurities, the composition relationship f1 is in the range of 7≤f1≤16, the composition relationship f2 is in the range of 0≤f2≤9, and the composition relationship f3 is 0.3 ≤f3≤1.3, the composition relation f4 is in the range of 2≤f4≤8, and the composition relation f5 is in the range of 18≤f5≤180.

Furthermore, in the copper alloy sheets according to the first to fourth embodiments of the present invention described above, the average crystal grain size is 2 to 9 μm.

In addition, in the copper alloy sheets according to the first and third embodiments of the present invention, the average particle size of the circular or elliptical precipitates is 3 to 75 nm, or the inner particle size of the precipitates is 3 to 75 nm. The ratio of the number of precipitates occupied was 70% or more.

In the copper alloy sheets according to the second and fourth embodiments of the present invention, the average particle size of the circular or elliptical precipitates is 3 to 60 nm, or the precipitates have an inner particle size of 3 to 60 nm. The ratio of the number of objects occupied is 70% or more.

In addition, in the copper alloy sheets according to the first to fourth embodiments of the present invention described above, the electrical conductivity is 24% IACS or more or the electrical conductivity is 26% IACS or more, and the stress relaxation resistance under the conditions of 150° C. and 1000 hours is stress relaxation. The relaxation rate is 25% or less or the stress relaxation rate is 23% or less under the conditions of 150°C and 1000 hours.

In addition, in the copper alloy sheets according to the first to fourth embodiments of the present invention, the balance index f6 is defined as follows as an index showing the balance between electrical conductivity and stress relaxation characteristics. When the electrical conductivity is C (%IACS) and the effective stress at 150°C and 1000°C is Pw (N/mm ² ), the balance index f6 is defined as f6=Pw×(C/100) ^1/2 . That is, the balance index f6 is the product of Pw and (C/100) ^1/2 . In this embodiment, it is preferable that Pw≥300 and f6≥190.

In addition, in the copper alloy sheets according to the first to fourth embodiments of the present invention, it is preferable that the yield strength YS ₉₀ in the direction of 90 degrees with respect to the rolling direction is between the yield strength YS ₀ in the direction of 0 degrees with respect to the rolling direction. The ratio YS ₉₀ /YS ₀ is in the range of 0.95≤YS ₉₀ /YS ₀ ≤1.07.

Hereinafter, the reasons for specifying the component composition, composition relational expressions f1, f2, f3, f4, f5, metal structure, and various properties as above will be described.

(Zn)

Zn is a main element constituting the copper alloy sheet of the present embodiment, and its atomic valence is divalent to reduce the stacking fault energy, increase the generation sites of recrystallization nuclei during annealing, and make the recrystallized grains finer or ultrafine. In addition, through the solid solution of Zn, the tensile strength, yield strength, spring characteristics, etc. are improved without impairing the bending workability, and the heat resistance and stress relaxation characteristics of the substrate are improved, and the solder wettability and migration resistance are also improved. sex. The low price of Zn lowers the specific gravity of the copper alloy and also has an economic advantage. Although it also depends on the relationship with other added elements such as Sn, Zn needs to be contained at least 4% by mass or more in order to exert the above effect. Therefore, the lower limit of the Zn content is 4% by mass or more, preferably 4.5% by mass or more, and most preferably 5% by mass or more. On the other hand, although it also depends on the relationship with other added elements such as Sn, even if it contains more than 14 mass % of Zn, it will affect the refinement of crystal grains and the improvement of strength, and not only will not show a significant effect commensurate with the content. As a result, the electrical conductivity decreases, the sensitivity to stress corrosion cracking increases, the Young's modulus decreases, the elongation and bending workability deteriorate, the stress relaxation characteristics decrease, and the solder wettability also deteriorates. Therefore, the upper limit of the Zn content is 14% by mass, preferably not more than 12% by mass and not more than 11% by mass, most preferably not more than 9% by mass. When Zn is in an appropriate composition range, the heat resistance of the matrix is improved, and the stress relaxation characteristics are improved through the interaction with Ni, Sn, and P, and it has excellent bending workability, high strength, and Young's modulus and desired electrical conductivity.

Even if the content of divalent Zn is within the above range, it is difficult to refine the crystal grains if Zn is added alone. In order to make the crystal grains finer to a predetermined particle size, it is necessary to add Sn, Ni, and P described later together, and the value of the composition relational expression f1 must be taken into consideration. Similarly, in order to improve heat resistance, stress relaxation characteristics, strength, and spring characteristics, it is necessary to add Sn, Ni, and P described later together, and the values of composition relations f1, f2, and f3 must be considered.

In addition, when Zn is 9% by mass or more, although high tensile strength and yield strength can be obtained, the bending workability, stress corrosion cracking resistance and stress relaxation characteristics are deteriorated with the increase of Zn as described above, and lower the Young's modulus. In order to improve these characteristics, the interaction with Ni or Sn and the values of the composition relations f1, f2, and f3 are more important.

(Sn)

Sn is the main element constituting the copper alloy sheet of this embodiment, and its atomic valence is tetravalent, so that the stacking fault energy is reduced, and by being contained in the copper alloy sheet together with Zn and Ni, the generation sites of recrystallization nuclei are increased during annealing, The recrystallized grains are miniaturized or ultra-micronized. In particular, co-addition with 4% by mass or more of divalent Zn and divalent Ni exhibits a remarkable effect even if a small amount of Sn is contained. In addition, Sn dissolves in the matrix to improve the tensile strength, yield strength, spring characteristics, etc., to improve the heat resistance of the matrix, to improve the stress relaxation characteristics, and to improve the stress corrosion cracking resistance. In order to exhibit the above effects, it is necessary to contain at least 0.1% by mass of Sn. Therefore, the lower limit of the Sn content is 0.1% by mass or more, most preferably 0.2% by mass or more. On the other hand, if a large amount of Sn is contained, the electrical conductivity will be deteriorated, the bending workability, Young's modulus and solder wettability will be deteriorated, and the stress relaxation characteristics and stress corrosion cracking resistance will be reduced instead. In particular, stress relaxation characteristics are largely influenced by the compounding ratio with Ni. Therefore, the upper limit of the content of Sn is 1% by mass or less, preferably 0.9% by mass or less, and most preferably 0.8% by mass or less.

(Cu)

Cu is the remainder of the main elements constituting the copper alloy sheet of the present embodiment. However, in order to ensure electrical conductivity and stress corrosion cracking resistance depending on the Cu concentration, and to maintain stress relaxation characteristics, elongation, Young's modulus, and solder wettability, the lower limit of the Cu content is preferably 84% by mass or more, and further Preferably it is 86 mass % or more. On the other hand, in order to obtain high strength, the upper limit of the Cu content is preferably 94.5% by mass or less, more preferably 94% by mass or less.

(P)

The atomic valence of P is pentavalent, and it has the effect of making crystal grains finer and suppressing the growth of recrystallized grains, but the latter effect is greater because of its small content. In addition, although the amount is small, P dissolved in the matrix and precipitates combining P and Ni have the effect of improving the stress relaxation characteristics. A part of P combines with Ni to be described later to form precipitates, and Ni can be mainly used as the case may be, and Co, Fe, etc. are combined to form precipitates, and the effect of inhibiting crystal grain growth can be further enhanced. In order to suppress the growth of crystal grains, there are circular or elliptical precipitates, it is necessary to make the average particle diameter of the precipitates 3-75nm or the ratio of the number of precipitated particles with a particle diameter of 3-75nm in the precipitated particles It is more than 70%. The effect or effect of the precipitates on inhibiting the growth of recrystallized grains during annealing is greater than that of precipitation strengthening, and is different from the strengthening effect only by precipitation. Furthermore, P has the effect of remarkably improving the stress relaxation characteristic which is one of the subject-matters of this application by interacting with Ni based on containing Zn and Sn in the said range.

In order to exert these effects, the lower limit of the content of P is 0.005 mass % or more, Preferably it is 0.008 mass % or more, Most preferably, it is 0.01 mass % or more. On the other hand, even if it contains more than 0.08% by mass, the effect of inhibiting the recrystallization grain growth by the precipitates is saturated, and if there are too many precipitates, the elongation, bending workability, and stress relaxation characteristics will be reduced. Therefore, the upper limit of the P content is preferably 0.08% by mass, preferably 0.07% by mass or less.

(Ni)

A part of Ni is combined with P to form a compound, and the rest is in solid solution. Ni interacts with P, Zn, and Sn contained in the concentration range specified above to improve stress relaxation characteristics, increase the Young's modulus of the alloy, improve solder wettability, and stress corrosion cracking resistance. The compounds formed inhibit the growth of recrystallized grains. In order to significantly exert these functions, it is necessary to contain 1% by mass or more. Therefore, the lower limit of the Ni content is 1% by mass or more, preferably 1.05% by mass or more, and most preferably 1.1% by mass or more. On the other hand, the increase of Ni hinders the electrical conductivity and saturates the stress relaxation characteristics, so the upper limit of the Ni content is 2.4% by mass or less, preferably 2.2% by mass or less, and most preferably 2% by mass or less. In addition, in the relationship with Sn, while satisfying the composition relational expression described later, especially in order to improve the stress relaxation characteristics, Young's modulus and bending workability, the content of Ni is preferably 1.8 times or more than the content of Sn, and it is more preferable to contain More than 2 times. This is because the stress relaxation characteristics are particularly improved by adding divalent Ni to 3.5 times or more, especially 4 times or more, the atomic concentration of tetravalent Sn. On the other hand, from the viewpoint of the relationship between strength and electrical conductivity and stress relaxation properties, the Ni content is preferably controlled to be 10 times or less, more preferably 8 times or less, and most preferably 6 times or less the Sn content.

(At least one or two or more selected from Al, Fe, Co, Mg, Mn, Ti, Zr, Cr, Si, Sb, As, Pb, and rare earth elements)

Al, Fe, Co, Mg, Mn, Ti, Zr, Cr, Si, Sb, As, Pb, and rare earth elements have the effect of improving various characteristics. Therefore, the copper alloy sheet of the third embodiment and the copper alloy sheet of the fourth embodiment contain at least one or two or more elements selected from these elements.

Here, Al, Fe, Co, Mg, Mn, Ti, Zr, Cr, Si, Sb, As, Pb, and rare earth elements make the crystal grains of the alloy finer. Al, Fe, Co, Mg, Mn, Ti, Zr form compounds together with P or Ni, suppress the growth of recrystallized grains during annealing, and have a large effect of making crystal grains finer. In particular, Fe and Co have a large effect, and form a compound of Ni and P containing Fe or Co to make the particle size of the compound finer. A fine compound further refines the size of the recrystallized grains during annealing and increases the strength. However, if this effect is excessive, bending workability and stress relaxation characteristics will be impaired. In addition, Al, Sb, and As have the effect of improving the stress corrosion cracking resistance and corrosion resistance of copper alloys, Sb having an atomic valence of pentavalent improves stress relaxation characteristics, and Pb has the effect of improving press formability.

In order to exert these effects, it is necessary to use at least one or two or more elements selected from Al, Fe, Co, Mg, Mn, Ti, Zr, Cr, Si, Sb, As, Pb, and rare earth elements Each contains 0.0005 mass % or more. On the other hand, if any one of the selected elements exceeds 0.05% by mass, the effect will not be saturated, but the bending workability will be hindered. In particular, if Fe, Co, etc., which easily form compounds with P, exceed 0.05% by mass, the stress relaxation characteristics will also be deteriorated. It is preferable that any selected element is also 0.03% by mass or less. In addition, if the total content of these elements exceeds 0.2% by mass, the effect will not be saturated, but the bending workability will be hindered. Therefore, the upper limit of the total content of these elements is 0.2 mass % or less, Preferably it is 0.15 mass % or less, More preferably, it is 0.1 mass % or less.

(unavoidable impurities)

Trace elements such as oxygen, hydrogen, carbon, sulfur, and water vapor are unavoidably contained in the raw materials including reflow materials and the manufacturing process mainly including when they are dissolved in the atmosphere. Of course, these unavoidable impurities are also contained in the copper alloy sheet.

Here, in the copper alloy of the present embodiment, elements other than the specified component elements can be regarded as unavoidable impurities, and the total content of unavoidable impurities is preferably 0.2% by mass or less, more preferably 0.1% by mass or less. Furthermore, elements other than Zn, Ni, Sn, P, and Cu among the elements specified in the copper alloy sheet according to the present embodiment may contain impurities smaller than the above-described specified lower limit range.

(composition relation f1)

When the compositional relation f1=[Zn]+3×[Sn]+2×[Ni] is 7, the alloy of this embodiment is a boundary value for obtaining high strength and also a boundary value for improving stress relaxation characteristics. Therefore, the lower limit of the composition relational expression f1 is 7 or more, preferably 7.5 or more. On the other hand, if the value of f1 exceeds 18, desired electrical conductivity cannot be obtained, and stress relaxation characteristics, stress corrosion cracking resistance, bending workability, and solder wettability are also adversely affected. Therefore, the upper limit of the composition relational expression f1 is 18 or less, preferably 16 or less, and most preferably 14 or less.

(composition relation f2)

When the composition relation f2=[Zn]-0.3×[Sn]-1.8×[Ni] is 11 or 10, it is the boundary value whether to cause cracking under severe stress corrosion cracking environment. It is also a boundary value for obtaining excellent ductility, bending workability, good solder wettability, and good stress relaxation characteristics. As mentioned above, the high susceptibility to stress corrosion cracking can be cited as a fatal defect of Cu-Zn alloys, but in the case of Cu-Zn alloys, the susceptibility to stress corrosion cracking depends on the content of Zn, and the Zn content is approximately 10% by mass as a boundary increases the sensitivity to stress corrosion cracking. Therefore, the upper limit of the composition relational expression f2 is 11, preferably 9 or less, and most preferably 8 or less. In addition, the composition relational expression f2=10 corresponds to a Zn content of 10% by mass or 9% by mass in the case of a Cu-Zn binary alloy. In the present application, within the composition range where Ni and Sn are co-added, the coefficient of Ni in the composition relational expression f2 is large, and by including Ni, the stress corrosion cracking sensitivity can be reduced particularly. On the other hand, if f2 is less than 0, the strength will decrease, so the lower limit of the composition relational expression f2 is 0 or more, preferably 0.5 or more, and more preferably 1 or more.

(composition relation f3)

Composition relation f3=(3×[Ni]+0.5×[Sn])/[Zn], that is, by properly setting the ratio of (3×[Ni]+0.5×[Sn]) to [Zn], even Zn containing 4 to 14% by mass also exhibits excellent stress relaxation characteristics. The value of f3 is 0.3 or more, that is, when the value of (3×[Ni]+0.5×[Sn]) relative to [Zn] is 0.3 or more, good stress relaxation characteristics are exhibited. Preferably it is 0.35 or more, More preferably, it is 0.4 or more. At the same time, it also improves solder wettability and stress corrosion cracking resistance. On the other hand, even if the value of f3 exceeds 1.6, the effect will not be saturated, but the electrical conductivity and stress relaxation characteristics will be deteriorated, and it is also economically problematic because it contains more expensive Sn and Ni than Zn. Therefore, the upper limit of the composition relational expression f3 is 1.6 or less, preferably 1.3 or less, and most preferably 1.2 or less.

(composition relation f4)

In the Cu-Zn-Ni-Sn-P alloy, the composition relation f4=[Ni]/[Sn] representing the blending ratio of Ni and Sn is very important in order to obtain good stress relaxation characteristics. When the mass concentration ratio of Ni having an atomic valence of 2 is 1.8 times that of Sn having an atomic valence of 4, and the stress relaxation characteristic is significantly improved when the atomic concentration ratio is 3.5 or more. The value of f4 is 2 or more, that is, if there are 4 or more divalent Ni atoms with respect to 1 tetravalent Sn atom, the stress relaxation characteristics are more excellent, and the bending workability and stress corrosion cracking resistance also become better. good. On the other hand, if there are too many Ni atoms, the stress relaxation characteristics will be saturated, and in some cases, it will be worse and the strength will also be lowered. The upper limit of the composition relational expression f4 is 10 or less, preferably 8 or less, and most preferably 6 or less. Within this range, the effects of Ni and Sn can be exhibited to the maximum.

(composition relation f5)

In addition, stress relaxation characteristics are affected by Ni, P, and compounds of Ni and P in a solid solution state. Here, if the composition relationship f5=[Ni]/[P] is less than 16, the ratio of the compound of Ni and P to Ni in a solid solution state increases, so the stress relaxation characteristics are deteriorated, and the bending workability is also deteriorated. Difference. That is, when the composition relational expression f5=[Ni]/[P] is 16 or more, preferably 18 or more, and most preferably 20 or more, the stress relaxation characteristics and bending workability become good. On the other hand, if the composition relational formula f5=[Ni]/[P] exceeds 250, the amount of the compound formed of Ni and P and the amount of P dissolved in solid solution will decrease, so the stress relaxation characteristics will deteriorate. In addition, the effect of refining crystal grains becomes small, and the strength of the alloy becomes low. Therefore, the upper limit of f5 is 250 or less, preferably 180 or less, and most preferably 120 or less.

(average grain size)

In the copper alloy sheet of the present embodiment, the average crystal grain size can be set to about 1.5 μm, although depending on the process. However, if the average grain size of the copper alloy sheet according to this embodiment is reduced to 1.5 μm, the proportion of grain boundaries formed with a width of about a few atoms increases, and elongation, bending workability, and stress Relaxation characteristics deteriorate. Therefore, in order to have high strength, high elongation, and good stress relaxation properties, it is necessary to set the average crystal grain size to 2.0 μm or more. The lower limit of the average crystal grain size is preferably 3 μm or more, most preferably 4 μm or more. On the other hand, as the crystal grains become larger, good elongation and bending workability are exhibited, but desired tensile strength and yield strength cannot be obtained. At least the average crystal grain size needs to be reduced to 9 μm or less. The upper limit of the average crystal grain size is preferably 8 μm or less, especially when strength is emphasized, it is 7 μm or less. As such, by setting the average crystal grain size within a narrower range, a highly excellent balance among bendability, elongation, strength, electrical conductivity, or stress relaxation characteristics can be obtained.

(precipitate)

For example, when annealing a rolled material that has been cold-rolled at a cold working rate of 50% or more, depending on time, if a certain critical temperature is exceeded, recrystallization nuclei will be generated centering on grain boundaries where processing strain has accumulated. Although it depends on the alloy composition, in the case of the copper alloy sheet of this embodiment, the grain size of the recrystallized grains generated after nucleation is 1 μm or 2 μm, or recrystallized grains smaller than that, but even if the rolled material is given The heat will not replace all the processed structures with recrystallized grains at one time. In order to replace all or, for example, 95% or more with recrystallized grains, a temperature higher than the temperature at which recrystallization nucleation starts or a time longer than the time at which recrystallization nucleation starts is required. During this annealing, the recrystallized grains formed initially grow with temperature and time, and the grain size becomes larger. In order to maintain a fine recrystallized grain size, it is necessary to suppress the growth of recrystallized grains. In order to suppress the growth of recrystallized grains, P and Ni are contained in this embodiment. Compounds generated by P and Ni (including precipitates of P and Ni) function as pins to suppress the growth of recrystallized grains. The properties of the compound itself and the particle size of the compound are important in order for the compound formed by P and Ni (including precipitates of P and Ni) to function as a pin as described above. That is, as a result of research, it has been found that in the composition range of the copper alloy sheet according to the present embodiment, the compound formed by P and Ni (including precipitates of P and Ni) hardly hinders elongation, and in particular, the particle size of the compound is When it is 3-75nm, it seldom hinders the elongation rate, but effectively inhibits the growth of crystal grains.

Contains precipitates of P and Ni that inhibit the growth of recrystallized grains. In the stage of the recrystallization heat treatment process, there are circular or elliptical precipitates, and the average particle size of the precipitates is 3 to 75nm or within the precipitated particles. The proportion of the number of objects having a diameter of 3 to 75 nm may be 70% or more. If the average particle size of the precipitates becomes small, the effects of precipitation strengthening of the precipitates and inhibition of grain growth are too large, and the recrystallized grains become small. Although the strength of the rolled material increases, the bending workability deteriorates. In addition, when the precipitates reach, for example, 100 nm, the effect of inhibiting the growth of crystal grains is almost lost, and the bending workability is deteriorated. In addition, the circular or elliptical precipitate includes not only a complete circular or elliptical shape but also a shape similar to a circular or elliptical shape.

In addition, in order to ensure the above-mentioned effect, the average particle size of the circular or elliptical precipitates is 3-60 nm or the proportion of the number of particles with a particle size of 3-60 nm in the precipitated particles is preferably 70% or more. The average particle diameter is most preferably 5 to 20 nm.

(Conductivity)

The copper alloy sheet of this embodiment is used in connectors, terminals, relays, springs, switches, semiconductors, lead frames, etc. used in automotive components, electrical components, electronic components, communication devices, and electronic/electrical devices. Therefore, the electrical conductivity is 24% IACS or more, preferably 26% IACS or more, and it is further necessary to secure 28% IACS or more.

(Stress relaxation resistance characteristics)

When terminals and connectors are used near the engine room of a car, for example, the temperature will rise to about 100°C. Therefore, when a stress of 80% of the alloy's yield strength is applied at 150°C and 1000 hours, the stress relaxation rate needs to be adjusted. It is 25% or less, preferably 23% or less, most preferably 20% or less. This is because if the stress relaxation rate becomes large, the strength (contact pressure, spring pressure) corresponding to the stress relaxation rate will actually be damaged. Alternatively, even the effective maximum contact pressure and spring pressure can be evaluated. That is, the effective maximum contact pressure, spring pressure (effective stress) Pw is expressed as, Pw = yield strength × 80% × (100% - stress relaxation rate (%)), not only the room temperature yield strength or 150°C and 1000 hours conditions The stress relaxation characteristic under is high, and the value in the previous formula is also expected to be high. If the yield strength × 80% × (100% - stress relaxation rate (%)) is 270N/ ^mm2 or more in the test under the condition of 150°C and 1000 hours, it is the lowest level of durability under high temperature conditions. If it is 300N/mm mm ² or more, it is suitable for use at high temperature, and it is most suitable if it is 330N/mm ² or more. By the way, in the case of Cu-30 mass% Zn, which is a representative alloy of brass with a yield strength of 500N/mm ² , in a test at 150°C and 1000 hours, the yield strength × 80% × (100%-stress The value of relaxation rate (%)) is about 70N/mm ² , and the yield strength of Cu-6 mass% Sn phosphor bronze of 550N/mm ² is about 180N/mm ² , which is still not satisfactory for current practical alloys.

(balance index f6)

In the rolled material after finish cold rolling, or the rolled material subjected to recovery heat treatment after finish cold rolling, or the rolled material subjected to reflow Sn plating or hot-dip Sn plating, in the W bending test at R/t=1.0 (R is the bending portion radius of curvature, t is the thickness of the rolled material), no cracks will occur, preferably on the premise that no cracks will occur when R/t=0.5, as an indicator of the balance between electrical conductivity and stress relaxation characteristics, the balance index f6=Pw× (C/100) ^1/2 becomes significant. When this balance index f6 is a high value, it can become a raw material of a terminal/connector suitable for the severe environment close to an engine room. That is, the product of (C/100) ^1/2 of the index of electrical characteristics and the effective stress can be used as an evaluation standard for terminals and connectors in a harsh environment close to the engine room. The balance index f6 needs to be at least 180 or more, preferably 190 or more, more preferably 200 or more is good, most preferably 210 or more.

(Yield strength ratio YS ₉₀ /YS ₀ )

Usually, if you observe the metal structure of the finish cold-rolled material, it shows that the crystal grains stretch in the rolling direction and compress in the thickness direction. There are differences in yield strength and bending workability. The specific metal structure, the crystal grains observed in the section parallel to the rolling surface are elongated crystal grains, and the crystal grains observed in the transverse section are compressed in the thickness direction, and the tensile strength of the rolled material sampled perpendicular to the rolling direction The strength TS ₉₀ and yield strength YS ₉₀ are higher than the tensile strength TS ₀ and yield strength YS ₀ of the rolled material sampled in the parallel direction, and the strength ratio TS ₉₀ /TS ₀ and yield strength ratio YS ₉₀ /YS ₀ exceed 1.05, It also exceeds 1.07, and sometimes reaches 1.1 depending on the situation. As the strength ratio TS ₉₀ /TS ₀ and the yield strength ratio YS ₉₀ /YS ₀ become higher than 1.05, the bending workability of the test piece sampled perpendicularly to the rolling direction deteriorates. On the contrary, depending on the manufacturing process, the strength ratio TS ₉₀ /TS ₀ and the yield strength ratio YS ₉₀ /YS ₀ are 0.97, and sometimes less than 0.95. In the anisotropy of the strength plane, the yield strength ratio YS ₉₀ /YS ₀ and the tensile strength ratio TS ₉₀ /TS ₀ are both preferably 1.07 or less, more preferably 1.05 or less, most preferably 1.03 or less or preferably 0.95 or more, and more preferably Preferably it is 0.97 or more, most preferably 0.99 or more. The copper alloy plate of this embodiment is used as the target terminals, connectors and other components when they are processed from rolled materials into products in actual use, the rolling direction and the perpendicular direction are often used, that is, the direction parallel to the rolling direction and the direction perpendicular to the rolling direction. These two directions require that there are no characteristic differences in tensile strength, yield strength, and bending workability from the actual use surface and the product processing surface to the rolling direction and the vertical direction.

In the copper alloy sheets according to the first to fourth embodiments of the present invention, the interaction and composition relational expressions f1 to f5 of Zn, Sn, P, and Ni are satisfied, the average crystal grain size is set to 2 to 9 μm, and P and Ni are The size of the formed precipitates and the ratio between these elements are controlled to a specified value, and the rolled material is produced by the following manufacturing process, so that the rolled material sampled in the direction of 0 degrees and the direction of 90 degrees relative to the rolling direction There is no difference in tensile strength and yield strength. Thus, in the copper alloy sheets according to the first to fourth embodiments of the present invention, the yield strength YS ₉₀ in the direction of 90 degrees relative to the rolling direction and the yield strength YS ₀ in the direction of 0 degrees relative to the rolling direction are obtained. The ratio YS ₉₀ /YS ₀ is in the range of 0.95≤YS ₉₀ /YS ₀ ≤1.07. In addition, in the present embodiment, the ratio TS ₉₀ /TS ₀ of the tensile strength TS ₉₀ in the direction 90 degrees to the rolling direction and the tensile strength TS ₀ in the direction 0 degrees relative to the rolling direction is 0.95. ≤TS ₉₀ /TS ₀ ≤1.07.

(other features)

In the copper alloy sheet according to the present embodiment, it is preferable that properties other than the above-mentioned electrical conductivity and stress relaxation resistance properties are defined as follows.

The copper alloy sheet according to the present embodiment preferably has high strength and has a bending workability when evaluated by W bending in various applications such that R/t≦1.0, more preferably R/t≦0.5. In particular, for terminals, connectors, and electrical/electronic components, for bending in two directions parallel and perpendicular to the rolling direction, it is more preferable that the bending workability is such that W bending is R/t≤1.0, more preferably R/t t≤0.5.

In addition, in general, Sn plating may be applied to the surfaces of terminals, connectors, and the like in view of corrosion resistance, contact resistance, and bonding. At this time, hot-dip Sn plating is performed in a coil (strip) state, Sn reflow plating is performed, or Sn plating is performed after forming a terminal or connector shape. Therefore, when it is used for terminal/connection equipment or electric/electronic components, it is necessary to have good Sn plating property, that is, good solder wettability. In addition, Sn plating is not a problem, especially in the coil state, but after forming terminals and connectors, Sn plating, especially when performing Pb-free solder plating, is not plated immediately after forming for production reasons, but placed for a while. Plating is performed after the period, and the surface is oxidized during the standing period, which may degrade the plating property and solder wettability. Material requirements, solder wettability is good, even if the surface is a little oxidized or the surface is not easy to oxidize, and the copper alloy with good solder wettability after being placed in the atmosphere. There are various evaluations of solder wettability, but from the viewpoint of industrial production, it is appropriate to evaluate the solder wettability time.

Next, the manufacturing method of the copper alloy sheet which concerns on 1st - 4th embodiment of this invention is demonstrated.

In addition, in this specification, processing performed at a temperature lower than the recrystallization temperature of the processed copper alloy material is referred to as cold processing, and processing performed at a temperature higher than the recrystallization temperature is referred to as hot processing, and these processings are processed by roll forming. Defined as cold rolling and hot rolling, respectively. Furthermore, recrystallization is defined as changing from one crystalline structure to another crystalline structure, or forming a brand new non-strained crystalline structure from a structure with strain caused by processing.

First, an ingot having the above composition is prepared, and the ingot is hot-worked (typically, hot-rolled). The starting temperature of hot rolling is to bring each element into a solid solution state, and it is set at 800°C or higher, preferably at 840°C or higher, and from the viewpoints of energy cost and hot ductility, it is set at 950°C or lower, preferably Set to 920°C. And, in order to further make P and Ni into a solid solution state, it is preferable to cool at a cooling rate of 1° C./sec or more at the temperature at the end of final rolling or in a temperature range from 650° C. to 350° C., so that at least these precipitates do not become Such as coarse precipitates that hinder elongation. If the precipitates become coarse in the hot rolling stage, it is difficult to eliminate them in heat treatments such as the subsequent annealing process, and hinder the elongation of the final rolled product.

In addition, when producing a plate-shaped ingot having a thickness of about 15 to 20 mm by the continuous casting method, hot working (hot rolling) can be omitted. At this time, homogenization heat treatment may be performed at 650° C. to 850° C. after casting. When not going through the hot rolling step, it is preferable to heat treatment at approximately 700°C or approximately 800°C for more than 1 hour, so that the coarse compound of Ni and P formed in the casting stage is temporarily in a solid solution state, and then the low-melting Sn, The concentration distribution of Ni etc. with a large content is uniform.

Furthermore, the copper alloy material is cold-rolled to a predetermined thickness, and recrystallization heat treatment is performed after cold-rolling. The cold rolling process, annealing process, or recrystallization heat treatment process is performed once or multiple times depending on the thickness of the final product.

As the annealing method and the recrystallization heat treatment method, there are a batch heat treatment method of heating and holding for a long time, and a continuous heat treatment method of high temperature and short time. The stress relaxation characteristics during the high-temperature-short-time heat treatment in the final recrystallization heat treatment method are particularly good. The reason for this is that P does not completely precipitate with Ni, but a certain concentration of P exists in a solid solution state. The recrystallization heat treatment process performed by high-temperature-short-time continuous heat treatment includes: a heating step of heating the copper alloy material to a predetermined temperature in a continuous heat treatment furnace; and a holding step of maintaining the copper alloy material at a predetermined temperature after the heating step. prescribed time; and a cooling step, after the holding step, the copper alloy material is cooled to a prescribed temperature, and in the recrystallization heat treatment process, the highest attained temperature of the copper alloy material is taken as Tmax (°C), which will be higher than that of the copper alloy material When the heating and holding time in the temperature range from the temperature 50°C lower than the maximum reaching temperature to the maximum reaching temperature is taken as tm (min), it is set as follows:

560≤Tmax≤790,

0.04≤tm≤1.0,

520≤It1=(Tmax−30×tm ^−1/2 )≤690.

Under the conditions of the final recrystallization heat treatment, if it is lower than the lower limit of the maximum attained temperature, holding time or heat treatment index It1 of the high-temperature-short-time continuous heat treatment condition, the non-recrystallized part will remain, or the average grain size will be less than 2 μm state of ultrafine crystal grains. Furthermore, if annealing is performed beyond the upper limit of the range of the maximum attained temperature, holding time, or heat treatment index It1, a fine metal structure with an average crystal grain size of 9 μm or less cannot be obtained. In addition, if the conditions are out of the range, the balance of Ni amount, P amount, Ni and P precipitates in solid solution will be disrupted, and the stress relaxation characteristics will be deteriorated.

In addition, when cooling in the recrystallization heat treatment step, in the temperature range from "maximum reaching temperature -50°C" to 400°C, cooling is preferably performed at a rate of 5°C/sec or more, more preferably at a rate of 10°C/sec or more. Cooling is performed under the condition of 15°C/sec or more, most preferably, the stress relaxation characteristic becomes good. When the cooling rate is slow, coarse precipitates appear, the ratio of P and Ni precipitates increases, the amount of P in solid solution decreases, and the stress relaxation characteristics and bending workability deteriorate.

In the recrystallization heat treatment process, in order to obtain uniform and fine recrystallized grains without mixed grains, it is far from enough to reduce the stacking fault energy alone. Therefore, in order to increase the generation position of recrystallization nuclei, strain based on cold rolling is required. Specifically For this purpose, the accumulation of strain in the grain boundaries is required. For this reason, the cold working ratio in the cold rolling before the recrystallization heat treatment step needs to be 55% or more, preferably 60% or more. On the other hand, if the cold working rate of cold rolling before the recrystallization heat treatment step is increased too much, problems such as strain will arise, so it is preferably 98% or less, most preferably 96% or less. That is, in order to increase the location of recrystallization nuclei based on physical effects, it is most effective to increase the cold working rate. Within the allowable strain range of the product, a higher working rate can be applied, thereby obtaining finer recrystallized grains.

In addition, the recrystallization heat treatment step can also be heat treated by batch annealing at a temperature ranging from 400° C. to 650° C. for 1 to 24 hours. However, regardless of high-temperature-short-time continuous heat treatment or batch annealing, it is necessary to adjust the conditions in the final heat treatment step so that the average crystal grain size and the grain size of precipitates fall within the above-mentioned predetermined size range. In addition, the final heat treatment process is preferably a high-temperature-short-time continuous heat treatment that can make a certain concentration of P into a solid solution state. If necessary, the intermediate recrystallization heat treatment, that is, the annealing process, can be batch-type or high-temperature-short-time continuous heat treatment. , has little effect on the characteristics of the final rolled product.

Next, finish rolling is performed on the copper alloy material subjected to the final recrystallization heat treatment step. After performing the finish cold rolling, heat treatment is carried out at a maximum reaching temperature of 150°C to 580°C, and a holding time of 0.02 to 100 minutes in the temperature range from "maximum reaching temperature -50°C" to the maximum reaching temperature, preferably satisfying the following definition The heat treatment index It2 is the recovery heat treatment process of the relationship of 120≤It2≤390.

Specifically, after the finish cold rolling process, it is preferable to manufacture by a recovery heat treatment process comprising: a heating step of heating the copper alloy material to a predetermined temperature; and a holding step of heating the copper alloy material at a predetermined temperature after the heating step. The copper alloy material is kept for a specified time; and a cooling step, after the keeping step, the copper alloy material is cooled to a specified temperature, and the maximum attained temperature of the copper alloy material is set as Tmax2 (°C), which will be higher than that of the copper alloy material When the heating retention time in the temperature range from the temperature 50°C lower than the maximum reaching temperature to the maximum reaching temperature is set as tm2 (min),

150≤Tmax2≤580,

0.02≤tm2≤100,

120≤It2=(Tmax2−25×tm2 ^−1/2 )≤390.

The recovery heat treatment process is not accompanied by recrystallization, and through low temperature or short-time recovery heat treatment, the stress relaxation rate, spring limit value, bending workability and elongation of the rolled material are improved, and it is used to recover the damage caused by cold rolling. Decreased electrical conductivity by heat treatment. In addition, in the heat treatment index It2, the lower limit is preferably 200 or more, and the upper limit is preferably 380 or less. By performing the recovery heat treatment step, the stress relaxation rate becomes about 1/2 compared with that before the heat treatment, the stress relaxation characteristics are improved, the spring limit value is increased by 1.5 to 2 times, and the electrical conductivity is increased by 0.5 to 2% IACS.

In addition, in the Sn plating process such as hot-dip Sn plating or reflow Sn plating, it is heated at about 150°C to about 300°C for a short time, but it is heated after being formed into terminals and connectors depending on the rolling material and the situation. Even if the Sn plating step is performed after the recovery heat treatment, the properties after the recovery heat treatment are hardly affected. On the other hand, the heating step in the Sn plating step is an alternative step to the recovery heat treatment step, and improves the stress relaxation characteristics, spring strength, and bendability of the rolled material.

The copper alloy sheets according to the first to fourth embodiments of the present invention are produced through the above production steps.

As described above, the copper alloy sheets according to the first to fourth embodiments of the present invention are excellent in stress corrosion cracking resistance and stress relaxation characteristics, high in strength, and good in bending workability. These characteristics make it an excellent cost-effective material suitable for electronic/electrical device components such as connectors, terminals, relays, and switches, and automotive components.

In addition, the average crystal grain size is 2 to 9 μm, and the electrical conductivity is 24% IACS or more, preferably 26% IACS or more. The upper limit is not particularly specified, but roughly speaking, if it is 42% IACS or less and there is a round or ellipse The precipitates, and the average particle size of the precipitates is 3 to 75nm, the balance of strength, strength and bending workability is further excellent, the balance of stress relaxation characteristics, stress relaxation characteristics and electrical conductivity, and the effective stress at 150 ° C Therefore, it becomes a raw material for electronic/electrical devices such as connectors, terminals, relays, switches, and automotive components that are suitable for use in harsh environments.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of this invention.

[Example]

The results of confirmation experiments conducted to confirm the effects of the present invention are shown below. In addition, the following examples are used to illustrate the effects of the present invention, and the structures, processes and conditions described in the examples do not limit the technical scope of the present invention.

Using the copper alloy sheets according to the first to fourth embodiments of the present invention and the copper alloy sheets of the comparative composition described above, samples were produced by changing the manufacturing process. The composition of the copper alloy is shown in Tables 1-3. In addition, Tables 1 to 3 show the values of the composition relational expressions f1, f2, f3, f4, and f5 shown in the above-mentioned embodiment.

The manufacturing steps of the samples were performed in three types, A, B, and C, and the manufacturing conditions were changed for each manufacturing step. Manufacturing process A is performed using actual batch equipment, and manufacturing processes B and C are performed using experimental equipment. Table 4 shows the manufacturing conditions of each manufacturing process. In addition, the heat treatment index of manufacturing process A8 and manufacturing process A9 is outside the setting condition range of this invention.

In manufacturing process A (A1-A33), raw materials were melted in an intermediate frequency melting furnace with an internal volume of 10 tons, and an ingot with a cross section of 190 mm in thickness and 630 mm in width was manufactured by semi-continuous casting. The ingot is cut into 1.5m lengths, and then, in steps A1 to A9 and A31 to A33, a hot rolling step (thickness of 13mm)-cooling step-milling step (thickness of 12mm)-first Cold rolling process (thickness 1.5mm) - annealing process (holding at 540°C for 4 hours), or (670°C, 0.24 minutes)) - second cold rolling process (thickness 0.5mm, cold working rate 67% )-final annealing process (recrystallization heat treatment process)-finish cold rolling process (plate thickness is 0.3mm, cold working rate 40%)-recovery heat treatment process. In the manufacturing process A10, the first cold rolling process and the annealing process are omitted. In addition, the above-mentioned holding time is the time of holding in a high temperature range from the highest reaching temperature to the highest reaching temperature -50°C.

The hot rolling start temperature in the hot rolling process was set at 860° C., and after hot rolling until the plate thickness reached 13 mm, water cooling was sprayed in the cooling process. In this specification, the hot rolling start temperature has the same meaning as the ingot heating temperature. The average cooling rate in the cooling step was measured at the rear end of the rolled strip as the temperature of the rolled material after final hot rolling or the average cooling rate in the temperature range from 650°C to 350°C. The measured average cooling rate was 4°C/sec.

In the recrystallization heat treatment process, the maximum reaching temperature Tmax (°C) of the rolled material and the holding time tm (min) in the temperature range from a temperature 50°C lower than the maximum reaching temperature of the rolled material to the maximum reaching temperature are changed to (690°C , 0.09min), (660°C, 0.07min), (710°C, 0.16min), (770°C, 0.25min) and (620°C, 0.06min). In addition, in the manufacturing process A1, recrystallization heat treatment was performed by batch annealing under the condition of holding at 470° C. for 4 hours. In addition, in the process of performing high-temperature-short-time recrystallization heat treatment, when cooling in steps A31 and A32, the average cooling rate in the range from a temperature 50° C. lower than the maximum reaching temperature of the rolled material to 400° C. is set to 3° C./ seconds and 12°C/sec, and the remaining processes were cooled at 20-30°C/sec.

In addition, as described above, the cold working rate in the finish cold rolling process was set to 40%.

In the recovery heat treatment process, set the maximum reaching temperature Tmax (°C) of the rolled material to 450 (°C), and set the holding time tm (min ) is set to 0.05 minutes. However, the recovery heat treatment process was not performed in the manufacturing process A6. Furthermore, in the manufacturing process A5, the obtained sample was heated in the electric furnace of 300 degreeC for 30 minutes, and it air-cooled. In manufacturing process A4, the obtained sample was completely immersed in a 350 degreeC oil bath for 0.07 minute, and it air-cooled. This heat treatment is a heat treatment condition equivalent to hot-dip Sn plating.

And, manufacturing process B (B1-B4) was performed as follows.

A laboratory test ingot with a thickness of 40 mm, a width of 120 mm, and a length of 190 mm was cut from the ingot of the manufacturing process A, followed by a hot rolling process (thickness 6 mm)-cooling process (spray water cooling) - pickling process - cold rolling process (thickness: 0.5 mm) - recrystallization heat treatment process - finish cold rolling process (plate thickness: 0.3 mm, processing rate 40%) - recovery heat treatment process.

In the hot rolling process, the ingot is heated to 860° C. and hot rolled to a thickness of 6 mm. The cooling rate in the cooling step (the temperature of the rolled material after hot rolling or the cooling rate when the temperature of the rolled material is 650° C. to 350° C.) was performed at 3° C./sec.

After cold rolling until the plate thickness reaches 0.5 mm, in the recrystallization heat treatment process, set Tmax to 690 (°C), hold time tm to 0.09 minutes, and set the average cooling rate from 640°C to 400°C at 25°C/sec . In the production process B1, the recrystallization heat treatment was performed by batch annealing under the condition of holding at 480° C. for 4 hours. In addition, it was cold-rolled to 0.3 mm in the finish cold-rolling process. In the production process B1 and the production process B2, the recovery heat treatment process was implemented under the conditions that Tmax was 450 (° C.) and the holding time tm was 0.05 minutes. In manufacturing process B4, it heated in the electric furnace of 300 degreeC for 30 minutes, and performed air cooling. In manufacturing process B3, the obtained sample was fully immersed in 250 degreeC oil bath for 0.15 minute, and it air-cooled. This heat treatment is also a heat treatment condition equivalent to hot-dip Sn plating.

In addition, in the production process B5 and the production process B5A, hot rolling was omitted, and after homogeneous annealing was performed at 700° C. for 4 hours, the sheet thickness was set to 6 mm by cold rolling, and annealing was performed at 620° C. for 4 hours. Then, the plate thickness was set to 0.5 mm by cold rolling, and in the manufacturing process B5, Tmax was set to 690 (°C), holding time tm was set to 0.09 minutes, and the average cooling rate from 640°C to 400°C was set to 25°C/sec The recrystallization heat treatment was carried out under the conditions of , while the recrystallization heat treatment was carried out under the condition of holding at 480° C. for 4 hours by batch annealing in the production process B5A. And in the finish cold rolling process, it cold-rolled to 0.3 mm, and implemented the recovery heat treatment process on the condition of heating in the electric furnace of 300 degreeC for 30 minutes.

In the production process B and the production process C described later, the process corresponding to the short-time heat treatment by the continuous annealing line in the production process A is replaced by the step of immersing the rolled material in the salt bath, and the maximum attained temperature is taken as As for the liquid temperature of the salt bath, the time taken to completely immerse the rolled material was used as the holding time, and air cooling was performed after immersion. In addition, a mixture of BaCl, KCl, and NaCl was used as the salt (solution).

Furthermore, manufacturing process C (C1, C1A, C2) was performed as follows as a laboratory test. Dissolving and casting were carried out so as to become predetermined components in the electric furnace of the laboratory to obtain a test ingot in the laboratory having a thickness of 40 mm, a width of 120 mm, and a length of 190 mm. Thereafter, it is manufactured in the same process as in the above-mentioned manufacturing process B. That is, the ingot is heated to 860°C and hot-rolled until the thickness reaches 6mm. After hot rolling, the cooling rate is 3°C/sec to 350°C when the temperature of the rolled material reaches the rolled material temperature after hot rolling or 650°C cooling within the temperature range. After cooling, the surface was pickled, and the plate thickness was adjusted to 0.5 mm by cold rolling. In the production process C1, the recrystallization heat treatment process was carried out under the conditions that Tmax was set to 690 (° C.), the holding time tm was set to 0.09 minutes, and the average cooling rate from 640° C. to 400° C. was set to 25° C./sec. On the other hand, in the production process C1A and the production process C2, the recrystallization heat treatment process was implemented at 470 degreeC for 4 hours and 380 degreeC for 4 hours, respectively. In addition, in the finish cold rolling process, the cold rolling was carried out to 0.3 mm, and the recovery heat treatment process was carried out under the condition of keeping at 300°C for 30 minutes in the electric furnace in the laboratory in the production process C1 and the production process C1A, and in the production process C2, the The recovery heat treatment process was performed under the condition of maintaining at 230° C. for 30 minutes.

As an evaluation of the copper alloy sheet produced by the above-mentioned method, observation of metal structure (average crystal grain size and average grain size of precipitates), electrical conductivity, stress relaxation characteristics, stress corrosion cracking resistance, solder wettability, Tensile strength, yield strength, elongation and bending workability were evaluated. The evaluation results are shown in Tables 5-20.

(average grain size)

For the measurement of the average grain size of recrystallized grains, select an appropriate magnification based on the grain size in the metal micrographs of 600 times, 300 times and 150 times, etc., according to the crystal grain size test method of copper-drawn products in JIS H 0501 quadrature method for determination. Additionally, twins are not considered grains. It is difficult to determine with a metal microscope when determined by the FE-SEM-EBSP (Electron Back Scattering diffraction Pattern) method. That is, JSM-7000F manufactured by JEOL Ltd. was used for FE-SEM, and TSL Solutions OIM-Ver.5.1 was used for analysis, and the average crystal grain size was obtained from the grain size diagram (grain diagram) at 200 times and 500 times the analysis magnification. The calculation method of the average crystal grain size is based on the quadrature method (JIS H 0501).

In addition, one crystal grain can be stretched by rolling, but the volume of the crystal grain is hardly changed by rolling. The crystal grain size in the recrystallization stage can be estimated from the average crystal grain size measured by the quadrature method in a cross section of the sheet material cut parallel to the rolling direction.

(particle size of precipitate)

The average particle diameter of the precipitates was determined as follows. For transmission electron images based on 500,000 times and 100,000 times (the detection limit is 1.0nm, 5nm respectively), use the image analysis software "Win ROOF" to make the contrast of the precipitates approximate to an ellipse, and aim at the The average value of the multiplication of the major axis and the minor axis was obtained for all the precipitated particles, and the average value was defined as the average particle diameter. In addition, in the measurement of 500,000 times and 100,000 times, the detection limits of particle diameters were set to 1.0 nm and 5 nm, respectively, and those smaller than these were regarded as unqualified and were not included in the calculation of the average particle diameter. In addition, with an average particle diameter of approximately 10 nm as a boundary, the smaller part is measured at 500,000 times, and the larger part is measured at 100,000 times. In the case of a transmission electron microscope, it is difficult to obtain accurate information on precipitates due to the high dislocation density in cold-worked materials. In addition, since the size of the precipitate does not change due to cold working, in this observation, the recrystallized portion after the recrystallization heat treatment process before the finish cold rolling process was observed. Two locations that enter the 1/4 length of the plate thickness from both surfaces of the rolled material, the front surface and the back surface, were set as measurement positions, and the measured values at the two locations were averaged.

(Conductivity)

The conductivity was measured using a conductivity measuring device (SIGMATEST D2.068) manufactured by FOERSTER JAPAN Ltd.. In addition, in this specification, "electric conduction" and "conduction" are used in the same meaning. In addition, since thermal conductivity and electrical conductivity are highly correlated, higher electrical conductivity indicates better thermal conductivity.

(Stress relaxation resistance characteristics)

According to JCBA T309:2004, the measurement of the stress relaxation rate was performed as follows. A cantilever beam threaded grip is used in the stress relaxation test of the material being tested. The test piece was sampled from the direction of 0 degrees (parallel) and the direction of 90 degrees (perpendicular) to the rolling direction, and the shape of the test piece was made into plate thickness t×width 10 mm×length 60 mm. The load stress on the tested material is set to 80% of the 0.2% yield strength, and exposed in the atmosphere of 150°C and 120°C for 1000 hours. The stress relaxation rate was obtained as follows.

Stress relaxation rate = (displacement after opening/displacement under stress load) × 100(%)

In the present invention, the value of the stress relaxation rate is preferably small.

In the evaluation at 120°C, the stress relaxation rate was 8% or less as evaluation A (excellent), more than 8% and 13% or less as evaluation B (good), and more than 13% as evaluation C (impossible). The stress relaxation characteristics required in this application are envisioned for high reliability and harsh situations.

In addition, the effective stress Pw under the conditions of 150° C. and 1000 hours was obtained by the following formula.

Pw=yield strength {(YS ₀ +YS ₉₀ )/2}×80%×(100%-stress relaxation rate (%))

Yield strength and stress relaxation characteristics depend on the relationship with the strip width after slitting, that is, when the width is less than 60 mm, it may not be possible to sample from a direction 90 degrees (perpendicular) to the rolling direction. At this time, the stress relaxation characteristics and Pw of the test piece were evaluated only in a direction 0° (parallel) to the rolling direction.

In addition, in tests No. T3 and T36 (alloy Nos. 1 and 3), it was confirmed that according to the stress in the direction of 90 degrees (perpendicular) to the rolling direction and the direction of 0 degrees (parallel) to the rolling direction The effective stress Pw calculated from the results of the relaxation test, the effective stress Pw calculated only from the results of the stress relaxation test in the direction at 0 degrees (parallel) to the rolling direction, and the effective stress Pw calculated only based on the results of the stress relaxation test at 90 degrees (perpendicular) to the rolling direction ) There is no large difference in the effective stress Pw calculated from the results of the stress relaxation test in the direction of ).

(balance index f6)

Based on the measured electrical conductivity C (%IACS) and effective stress Pw (N/mm ² ), the balance index f6 was calculated by the following formula.

f6＝Pw×(C/100) ^1/2

(stress corrosion cracking resistance)

The measurement of the stress corrosion cracking resistance was carried out using a test container and a test solution specified in JIS H 3250, and a solution obtained by mixing equal amounts of ammonia water and water.

In the stress corrosion cracking test, in order to investigate the sensitivity of stress corrosion cracking to the load stress, the rolled material to which a bending stress of 80% of the yield strength was applied was exposed to the above-mentioned ammonia atmosphere using a resin cantilever beam clamp. The stress relaxation rate was used to evaluate the stress corrosion cracking resistance. That is, if a fine crack occurs, it will not recover, and if the degree of the crack increases, the stress relaxation rate will increase, so the stress corrosion cracking resistance can be evaluated. Those with a stress relaxation rate of 25% or less after 48 hours of exposure were evaluated as those with excellent corrosion cracking resistance, and those with a stress relaxation rate of more than 25% after 48 hours of exposure but 25% or less after 24 hours of exposure were regarded as those with excellent corrosion cracking resistance. Those with good stress corrosion cracking resistance (no practical problem) were evaluated as B, and those with a stress relaxation rate exceeding 25% after 24 hours of exposure were evaluated as C as those with poor stress corrosion cracking resistance (practically problematic). . In addition, the stress corrosion cracking resistance required in this application is envisioned in high reliability and harsh situations.

(solder wettability)

Solder wettability is carried out by wetting balance method (meniscograph). The test equipment is model SAT-5200 manufactured by PHESCA (RHESCA). A test piece is sampled from the rolling direction, and cut into thickness: 0.3 mm x width: 10 mm x length: 25 mm. The solder used was Sn-3.5% by mass Ag-0.7% by mass Cu and pure Sn. Acetone degreasing→15% sulfuric acid washing→water washing→acetone degreasing was performed as pretreatment. As the flux, an ordinary rosin flux (NA200 manufactured by Tamura Seisakusho Co., Ltd.) was used. The evaluation test was implemented under the conditions that the solder bath temperature was 270° C., the immersion depth was 2 mm, the immersion speed was 15 mm/sec, and the immersion time was 15 sec.

The evaluation of solder wettability was performed with zero crossing time. That is, it is the time required for the solder to become completely wet after dipping in the bath, and if the zero-crossing time is within 5 seconds, that is, if the solder is completely wet within 5 seconds after dipping in the solder bath, it is regarded as a measure of solder wettability in practical use. There was no problem in this aspect, so it was evaluated as B, and when the zero-crossing time was within 2 seconds, it was especially excellent, and it was evaluated as A. When the zero-crossing time exceeds 5 seconds, it is evaluated as C because there is a practical problem. In addition, after the final process of finishing rolling or recovery heat treatment, the sample was cleaned with sulfuric acid, and the surface was ground with No. 800 abrasive paper to obtain an unoxidized surface, which was placed in an indoor environment for 3 days or 10 days. In addition, in the table, "-1" and "-2" are the test results of using Sn-3.5 mass% Ag-0.7 mass% Cu flux for 3 days and 10 days respectively, "-3" is using pure Sn, 3 day test results.

(mechanical properties)

According to the method specified in JIS Z 2201 and JIS Z 2241, the measurement of tensile strength, yield strength and elongation was carried out in the shape of the test piece of No. 5 test piece. The test was performed in a direction of 0° with respect to the rolling direction and a direction of 90° with respect to the rolling direction.

(bending workability)

Bending workability was evaluated by W bending with a bending angle of 90 degrees specified in JIS H 3110. The bending test (W bending) was performed as follows. The bending radius (R) at the tip of the bending jig is 1 time (bending radius=0.3mm, R/t=1.0) or 0.5 times (bending radius=0.15mm, R/t=0.5) the material thickness (t). Samples were taken from a direction called the Bad Way, ie, a direction at 90 degrees relative to the rolling direction, and a direction called the Good Way, ie, a direction at 0 degrees from the rolling direction. Observe with a 50 times solid microscope and judge the bending workability according to whether there is crack. 1.0 times the thickness of the material and no cracks were evaluated as B, and those that were 1 times the thickness of the material (R/t=1.0) and cracks were evaluated as C. In addition, the bending workability of R/t≦0.5 means that cracks do not occur in a bending test in which the bending radius is 0.5 times or less the material thickness (R/t=0.5).

[Table 1]

[Table 2]

[table 3]

[Table 4]

[table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

[Table 11]

[Table 12]

[Table 13]

[Table 14]

[Table 15]

[Table 16]

[Table 17]

[Table 18]

[Table 19]

[Table 20]

According to the above evaluation results, the composition, composition relationship and characteristics confirmed are as follows:

The results of the compositions of the copper alloy sheets are as follows. In addition, comparative alloys are as follows.

The Zn content of alloy Nos. 100 and 121 is less than the composition range of the invention alloy.

The Sn content of alloy No. 101 is less than the composition range of the invention alloy.

The P content of alloy No. 102 is more than the composition range of the invention alloy.

The Zn content of Alloy No. 103 is more than the composition range of the invention alloy.

The P content of Alloy No. 104 is less than the composition range of the inventive alloy.

The Sn content of alloy No. 105 is larger than the composition range of the invention alloy.

The Ni content of alloy Nos. 106 and 122 is less than the composition range of the invention alloy.

Alloy No. 107 does not satisfy the ranges of the composition relational expressions f2 and f3 of the invention alloy.

Alloy Nos. 108 and 109 do not satisfy the range of composition relation f1 of the invention alloy.

Alloy Nos. 110 to 113 did not satisfy the range of composition relation f4 of the invention alloy.

Alloy No. 114 does not satisfy the range of composition relation f3 of the invention alloy.

Alloy Nos. 115 and 116 do not satisfy the range of composition relation f5 of the invention alloy.

Alloy No.118-120 are common brass.

Alloy Nos. 117 and 123 have relatively high Fe and Co contents.

(1) If the P content is more than the range of the alloy of the present invention, the average grain size of the precipitated particles after the recrystallization heat treatment process is small, the average crystal grain size becomes small, and the bending workability and stress relaxation rate become poor (refer to Alloy No. .102 etc.). If the P content is less than the range of the alloy of the present invention or greater than the range 250 set by Ni/P in the composition relationship f5, the average grain size and the average crystal grain size of the precipitated particles after the recrystallization heat treatment process will become large, and the tensile strength will increase. The strength and yield strength become lower, and the stress relaxation rate becomes worse. When Ni/P is 180 or less, and further 120 or less, the tensile strength and yield strength become high, and the stress relaxation rate becomes favorable. If Ni/P in f5 is less than the set range, the bending workability and stress relaxation rate will deteriorate (refer to alloy Nos. 104, 116, 115, 13, 18, etc.).

(2) If the Zn content is less than the range of the alloy of the present invention, the average crystal grain size after the recrystallization heat treatment step becomes large, and the tensile strength becomes low. Also, the effect corresponding to the Ni content cannot be obtained, and the stress relaxation rate becomes poor (see Alloy No. 100, etc.). About 4% by mass of Zn is a boundary value for satisfying the tensile strength, stress relaxation characteristics, and effective stress Pw (refer to alloy No. 1, 10, 100, etc.). If the Zn content exceeds the conditional range of the inventive alloy, the electrical conductivity, tensile strength, yield strength, stress relaxation rate, bending workability, stress corrosion cracking resistance, and solder wettability will deteriorate. When the Zn content is 12% by mass or less, and further 10% by mass or less, the above-mentioned properties become good (refer to alloy Nos. 103, 12, 15, 18, etc.).

(3) When the Sn content is more than the range of the present invention, bending workability and stress relaxation characteristics will also deteriorate, and electrical conductivity will also decrease. With respect to the rolling direction, the tensile strength and yield strength in the perpendicular direction become larger. On the other hand, if the Sn content is less than the range of the present invention, the strength will be low and the stress relaxation characteristics will be deteriorated. If the Ni content is small, excellent stress relaxation properties cannot be obtained, but if the Ni content exceeds 1.0% by mass, the stress relaxation properties become good (see alloy Nos. 101, 105, 106, 122, 17, 19, etc.).

(4) If the composition relationship f1 is less than the condition range of the inventive alloy, the average grain size after the recrystallization heat treatment process is relatively large, the tensile strength and yield strength are low, and the stress relaxation characteristics cannot be obtained corresponding to the Ni content. effect, but worse. If the compositional relational expression f1 is greater than the conditional range of the inventive alloy, the stress corrosion cracking resistance, bending workability, and solder wettability are poor, and the electrical conductivity is also low. Furthermore, the effect corresponding to the Ni content cannot be obtained, and the stress relaxation characteristic is inferior. The lower limit of the value of f1 is approximately 7, and the upper limit is approximately 18 or approximately 16, which correspond to boundary values of these characteristics. If the value of f1 is less than 14, the characteristics become slightly better (refer to alloy Nos. 108, 109, 12, 1, 15, 18, etc.).

(5) If the composition relational expression f2 is larger than the condition range of the inventive alloy, the stress corrosion cracking resistance is deteriorated, and the stress relaxation characteristic and bending workability are also inferior. When the value of the composition relation f2 is 9-11, it is related to whether these characteristics are good or not, and is equivalent to the boundary value. If the value of f2 is less than 8, the stress corrosion cracking resistance, stress relaxation characteristics and bending workability will be improved (refer to alloy Nos. 107, 103, 12, 15, 18, etc.).

(6) If the composition relational expression f3 is smaller than the conditional range of the inventive alloy, the stress corrosion cracking resistance, stress relaxation characteristics and bending workability will deteriorate. The boundary value of f3 is about 0.3 to 0.35. If the value of f3 is greater than 0.4, the stress corrosion cracking resistance, stress relaxation characteristics, and bending workability become good (refer to alloy Nos. 107, 114, 2, 15, etc.).

(7) If the composition relational expression f4 is smaller than the conditional range of the invention alloy, the stress relaxation characteristics will deteriorate, and the bending workability and stress corrosion cracking resistance will also decrease. With respect to the rolling direction, the tensile strength and yield strength in the perpendicular direction become larger. If the composition relational expression f4 is larger than the condition range of the invention alloy, the stress relaxation characteristic will deteriorate (refer to alloy Nos. 110 to 113, 14, 17, etc.).

As mentioned above, even if the concentrations of Zn, Sn, Ni, and P are within the specified concentration ranges, if the values of the composition relational expressions f1, f2, f3, f4, and f5 are not within the specified ranges, the stress corrosion cracking resistance and stress relaxation properties cannot be satisfied. Any of properties, strength, bendability, solder wettability, and electrical conductivity.

(8) If one or more elements selected from the group consisting of Al, Fe, Co, Mg, Mn, Ti, Zr, Cr, Si, Sb, As, and Pb are contained, it can be confirmed that the strength and the Stress relaxation characteristics, stress corrosion cracking resistance (refer to alloy No.20~32, etc.).

(9) When 0.08% by mass of Fe or 0.07% by mass of Co is contained, the average crystal grain size becomes small, and bending workability and stress relaxation characteristics deteriorate (refer to Alloy Nos. 117 and 123).

And, when using the copper alloy sheet of the present invention, it is as follows:

(1) In the example alloys of manufacturing process A using mass production equipment and manufacturing process B using experimental equipment, if the manufacturing conditions are the same, in the metal structure after the recrystallization heat treatment of the two processes, the average crystal grains and precipitates The size of the material is the same, the average particle size is almost the same, and almost the same mechanical properties, stress relaxation characteristics (including stress relaxation rate, effective stress relaxation characteristics and 1/2 product of effective stress and electrical conductivity) can be obtained. Stress corrosion cracking resistance and solder wettability (refer to test No.T10, T12, T26, T28, etc.).

(2) There is no difference in the average grain size regardless of whether annealing is performed once or twice (recrystallization heat treatment process), and almost the same mechanical properties, stress relaxation characteristics, stress corrosion cracking resistance, and solder wettability can be obtained (see Test No.T2, T3, T10, T18, T19, T26, etc.).

(3) The stress relaxation characteristics are better when high temperature-short time heat treatment is performed in the final recrystallization heat treatment process than during batch annealing (refer to test No. T1, T2, T3, T17, T18, T19, T102, T103, etc.). In addition, in the high-temperature-short-time heat treatment, the cooling rate was limited to 5° C./sec, and the stress relaxation was slightly improved. When it is 10°C/sec or more or 15°C/sec or more, it is slightly better. In addition, compared with the average crystal grain size of 3 to 4 μm, the yield strength at 5 to 7 μm is slightly lower, but the stress relaxation characteristics are slightly better (reference test No. T18, T23, T34, T39, T50, T55, T3A, T3B, T3, etc.).

(4) Even in the process without the hot rolling process, the particle size of the precipitate is slightly larger than that of the process after the hot rolling process, but almost the same mechanical properties, stress relaxation characteristics, stress corrosion cracking resistance and Solder wettability (refer to Test No.T14, T15, T46, T47, etc.).

(5) When the coefficient It1 of the recrystallization heat treatment is large within the set range, the average crystal grain size and precipitates become large, the yield strength is slightly lower, and the stress relaxation characteristics are slightly better. If the coefficient It1 of recrystallization heat treatment is small within the set range, the average crystal grain size and precipitates become smaller, the yield strength is slightly higher, but the stress relaxation characteristics are slightly worse. If It1 is lower than the set conditions, the recrystallized structure will not be completely formed, and the bending workability will deteriorate. If It1 is too large, the average crystal grain size becomes large, the particle size of precipitates also becomes large, the yield strength is low, and the stress relaxation characteristics are also low (refer to Test No. T3, T3C, T7, T8, T9, etc.).

(6) When the value of f1 is approximately 16, which is close to the upper limit, the bending workability and solder wettability are slightly deteriorated, and the sensitivity to stress corrosion cracking resistance is slightly increased (see alloy Nos. 12, 27, etc.).

(7) When the value of f2 is approximately 9, the sensitivity to stress corrosion cracking resistance becomes slightly higher (refer to alloy Nos. 15, 20, 22, etc.).

(8) If the value of f3 is lower than the set range of approximately 0.35, the stress relaxation characteristics are slightly deteriorated, and the sensitivity to stress corrosion cracking resistance is slightly increased (refer to alloy Nos. 20, 27, 31, etc.).

(9) If the value of f4 is slightly lower than the set range of 1.8 to 2, the stress relaxation characteristics are slightly deteriorated (refer to alloy No. 14, etc.).

(10) If the value of f5 is about 19 which is lower than the set range, and is about 250 which is close to the upper limit, the stress relaxation characteristic is slightly deteriorated (refer to alloy No. 13, 15, etc.).

(11) When Co and Fe are contained, the average crystal grain size becomes smaller, the tensile strength and yield strength become higher, but the elongation becomes lower, and the bending workability slightly deteriorates (refer to alloy No. 22, 123, etc.).

(12) Even if the recovery heat treatment conditions are set to the conditions equivalent to Sn plating, compared with copper alloy materials produced under other recovery heat treatment conditions before recovery heat treatment, almost the same tensile strength and yield strength can be obtained. Strength, stress relaxation characteristics, bending workability, elongation, electrical conductivity, stress corrosion cracking resistance and solder wettability (refer to test No.T3~T6, T12~T14, T19~T22, T28~30, etc.).

(13) Even if the final heat treatment is performed by intermittent annealing at 470°C for 4 hours or 480°C for 4 hours, the stress relaxation characteristics are slightly worse than high-temperature short-time annealing, but the tensile strength, yield strength, bending process properties, elongation and stress corrosion cracking resistance, with good properties (refer to test No.T1, T2, T11, T12, T15, T16, T102, T103, etc.).

Industrial availability

The copper alloy sheet of the present invention has excellent stress corrosion cracking resistance and stress relaxation properties, high strength, good solder wettability, and an excellent balance of strength, bending workability, effective stress relaxation properties, and electrical conductivity. Therefore, the copper alloy sheet of the present invention can be suitably used not only as connectors and terminals, but also as structural materials for electrical/electronic components such as relays, springs, switches, semiconductor applications, and lead frames.

Claims (14)

1. A copper alloy plate, characterized in that, Contains 4 to 14% by mass of Zn, 0.1 to 0.9% by mass of Sn, 0.005 to 0.08% by mass of P, and 1.0 to 2.4% by mass of Ni, and the remainder is composed of Cu and unavoidable impurities. The content of Zn [Zn] mass %, the content of Sn [Sn] mass %, the content of P [P] mass %, and the content of Ni [Ni] mass % have the following relationship: 7≤[Zn]+3×[Sn]+2×[Ni]≤18, 0≤[Zn]-0.3×[Sn]-1.8×[Ni]≤11, 0.3≤(3×[Ni]+0.5×[Sn])/[Zn]≤1.6, 2≤[Ni]/[Sn]≤10, 16≤[Ni]/[P]≤250, The average crystal grain size is 2-9 μm, The average particle diameter of the circular or elliptical precipitates is 3 to 75 nm, or the ratio of the number of precipitates with a particle diameter of 3 to 75 nm among the precipitates is 70% or more, Conductivity above 24% IACS, As the stress relaxation resistance characteristic, the stress relaxation rate at 150° C. for 1000 hours is 25% or less. 2. A copper alloy plate, characterized in that, Contains 4 to 12 mass % of Zn, 0.1 to 0.85 mass % of Sn, 0.008 to 0.07 mass % of P and 1.05 to 2.2 mass % of Ni, and the remainder is composed of Cu and unavoidable impurities, The content of Zn [Zn] mass %, the content of Sn [Sn] mass %, the content of P [P] mass %, and the content of Ni [Ni] mass % have the following relationship: 7≤[Zn]+3×[Sn]+2×[Ni]≤16, 0≤[Zn]-0.3×[Sn]-1.8×[Ni]≤9, 0.3≤(3×[Ni]+0.5×[Sn])/[Zn]≤1.3, 2≤[Ni]/[Sn]≤8, 18≤[Ni]/[P]≤180, The average crystal grain size is 2-9 μm, The average particle diameter of the circular or elliptical precipitates is 3 to 60 nm, or the ratio of the number of precipitates with a particle diameter of 3 to 60 nm among the precipitates is 70% or more, Conductivity above 26% IACS, As the stress relaxation resistance characteristic, the stress relaxation rate at 150° C. for 1000 hours is 23% or less. 3. The copper alloy plate according to claim 1 or 2, characterized in that, The copper alloy plate further contains 0.0005% by mass to 0.05% by mass and a total of 0.0005% by mass to 0.2% by mass, selected from Al, Fe, Co, Mg, Mn, Ti, Zr, Cr, Si, At least one or two or more of Sb, As, Pb, and rare earth elements. 4. The copper alloy plate according to claim 1 or 2, characterized in that, When C is the electrical conductivity, Pw is the effective stress at 150°C, and 1000 hours, the following relationship exists, where the unit of electrical conductivity is %IACS and the unit of effective stress is N/mm ² : Pw≥300, Pw×(C/100) ^1/2 ≥190, The ratio YS ₉₀ /YS ₀ of the yield strength YS ₉₀ in the direction of 90 degrees relative to the rolling direction to the yield strength YS ₀ in the direction of 0 degrees relative to the rolling direction is in the range of 0.95≤YS ₉₀ /YS ₀ ≤1.07 . 5. The copper alloy plate according to claim 3, characterized in that, When C is the electrical conductivity, Pw is the effective stress at 150°C, and 1000 hours, the following relationship exists, where the unit of electrical conductivity is %IACS and the unit of effective stress is N/mm ² : Pw≥300, Pw×(C/100) ^1/2 ≥190, The ratio YS ₉₀ /YS ₀ of the yield strength YS ₉₀ in the direction of 90 degrees relative to the rolling direction to the yield strength YS ₀ in the direction of 0 degrees relative to the rolling direction is in the range of 0.95≤YS ₉₀ /YS ₀ ≤1.07 . 6. The copper alloy plate according to claim 1 or 2, characterized in that, This copper alloy plate is used in electronic/electrical device components. 7. The copper alloy plate according to claim 3, characterized in that, This copper alloy plate is used in electronic/electrical device components. 8. The copper alloy sheet according to claim 4, characterized in that, This copper alloy plate is used in electronic/electrical device components. 9. The copper alloy plate according to claim 1 or 2, characterized in that, This copper alloy plate is used for connectors, terminals, relays, switches or semiconductors. 10. The copper alloy sheet according to claim 3, characterized in that, This copper alloy plate is used for connectors, terminals, relays, switches or semiconductors. 11. The copper alloy sheet according to claim 4, characterized in that, This copper alloy plate is used for connectors, terminals, relays, switches or semiconductors. 12. A method for manufacturing a copper alloy sheet, characterized in that it is a method for manufacturing the copper alloy sheet according to any one of claims 1 to 11, The method sequentially comprises a hot rolling process, a cold rolling process, a recrystallization heat treatment process and a finishing cold rolling process, The cold working rate in the cold rolling step is 55% or more, The recrystallization heat treatment process includes: a heating step, using a continuous heat treatment furnace, to heat the cold-rolled copper alloy material to a specified temperature; a holding step, after the heating step, maintaining the copper alloy material at a specified temperature for a specified time; and a cooling step, after the holding step, the copper alloy material is cooled to a predetermined temperature, and in the recrystallization heat treatment process, the maximum attained temperature of the copper alloy material is set as Tmax°C, which is higher than that of the copper alloy material When the heating holding time in the temperature range from the temperature 50°C lower than the maximum reaching temperature to the maximum reaching temperature is tm minutes, set 560≤Tmax≤790, 0.04≤tm≤1.0, ^520≤It1 =(Tmax-30×tm-1/2)≤690, In addition, in the recrystallization heat treatment step, cooling is performed at a temperature of 5° C./second or more in a temperature range from a temperature lower than the maximum attained temperature by 50° C. to 400° C. 13. The manufacturing method of the copper alloy plate according to claim 12, characterized in that, The method has a recovery heat treatment step implemented after the finish cold rolling step, The recovery heat treatment process includes: a heating step of heating the copper alloy material after finish cold rolling to a predetermined temperature; a holding step of maintaining the copper alloy material at a predetermined temperature for a predetermined time after the heating step; and a cooling step of After the holding step, the copper alloy material is cooled to a predetermined temperature, the maximum attainable temperature of the copper alloy material is set as Tmax 2°C, and the temperature range from the temperature 50°C lower than the maximum attainable temperature of the copper alloy material to the maximum attainable temperature When the holding time of medium heating is set to tm2 minutes, set 150≤Tmax2≤580, 0.02≤tm2≤100, 120≤It2=(Tmax2−25×tm2 ^−1/2 )≤390. 14. A method for manufacturing a copper alloy sheet, characterized in that it is a method for manufacturing the copper alloy sheet according to any one of claims 1 to 11, This method is constituted such that, without hot working, after performing one or more paired cold rolling steps and annealing steps, a combination of cold rolling steps and recrystallization heat treatment steps, and as the final cooling step implemented in the manufacturing process are performed. Any one or both of the combination of the finishing cold rolling process and the recovery heat treatment process of the rolling process, The cold working ratio in the cold rolling step performed just before the recrystallization heat treatment step is 55% or more, The recrystallization heat treatment process includes: a heating step, using a continuous heat treatment furnace, to heat the cold-rolled copper alloy material to a specified temperature; a holding step, after the heating step, maintaining the copper alloy material at a specified temperature for a specified time; and a cooling step, after the holding step, the copper alloy material is cooled to a predetermined temperature, and in the recrystallization heat treatment process, the maximum attained temperature of the copper alloy material is set as Tmax°C, which is higher than that of the copper alloy material When the heating holding time in the temperature range from the temperature 50°C lower than the maximum reaching temperature to the maximum reaching temperature is tm minutes, set 560≤Tmax≤790, 0.04≤tm≤1.0, ^520≤It1 =(Tmax-30×tm-1/2)≤690, In addition, in the recrystallization heat treatment step, cooling is performed at a temperature of 5° C./second or more in a temperature range from a temperature lower than the maximum attained temperature by 50° C. to 400° C., The recovery heat treatment process includes: a heating step of heating the copper alloy material after finish cold rolling to a predetermined temperature; a holding step of maintaining the copper alloy material at a predetermined temperature for a predetermined time after the heating step; and a cooling step of After the holding step, the copper alloy material is cooled to a predetermined temperature, the maximum attainable temperature of the copper alloy material is set as Tmax 2°C, and the temperature range from the temperature 50°C lower than the maximum attainable temperature of the copper alloy material to the maximum attainable temperature When the holding time of medium heating is set to tm2 minutes, set 150≤Tmax2≤580, 0.02≤tm2≤100, 120≤It2=(Tmax2−25×tm2 ^−1/2 )≤390.